diff --git a/xml/System.Net.Http/ByteArrayContent.xml b/xml/System.Net.Http/ByteArrayContent.xml
index a2e84f09999..816dc8a58d6 100644
--- a/xml/System.Net.Http/ByteArrayContent.xml
+++ b/xml/System.Net.Http/ByteArrayContent.xml
@@ -156,10 +156,17 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="0" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Creates an HTTP content stream for reading. It uses the memory from the <see cref="T:System.Net.Http.ByteArrayContent" /> as a backing store.</summary>
+        <returns>The HTTP content stream.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the content stream has been created.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="CreateContentReadStreamAsync">
@@ -226,11 +233,18 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Optional information about the transport, like the channel binding token. This parameter can be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Serializes and writes the byte array provided in the constructor to an HTTP content stream.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until the whole byte array has been written to `stream` or until `cancellationToken` cancels the operation.
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SerializeToStreamAsync">
diff --git a/xml/System.Net.Http/DelegatingHandler.xml b/xml/System.Net.Http/DelegatingHandler.xml
index df6a7a407a5..8b1049bd50f 100644
--- a/xml/System.Net.Http/DelegatingHandler.xml
+++ b/xml/System.Net.Http/DelegatingHandler.xml
@@ -221,11 +221,20 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send to the server.</param>
+        <param name="cancellationToken">A cancellation token to cancel operation.</param>
+        <summary>Sends an HTTP request to the inner handler to send to the server.</summary>
+        <returns>An HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ This operation blocks until the entire response, including content, is read.
+  
+ The <xref:System.Net.Http.DelegatingHandler.Send%2A> method is mainly used by the system and not by applications. When this method is called, it calls the <xref:System.Net.Http.DelegatingHandler.Send%2A> method on the inner handler.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/HttpClient.xml b/xml/System.Net.Http/HttpClient.xml
index 2b181b67acf..3262666123a 100644
--- a/xml/System.Net.Http/HttpClient.xml
+++ b/xml/System.Net.Http/HttpClient.xml
@@ -2686,10 +2686,31 @@ The <paramref name="requestUri" /> is not an absolute URI.
         <Parameter Name="request" Type="System.Net.Http.HttpRequestMessage" Index="0" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send.</param>
+        <summary>Sends an HTTP request with the specified request.</summary>
+        <returns>An HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ This operation blocks until the entire response, including content, is read.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">The HTTP version is 2.0 or higher or the version policy is set to <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+The custom class derived from <see cref="T:System.Net.Http.HttpContent" /> does not override the <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+The custom <see cref="T:System.Net.Http.HttpMessageHandler" /> does not override the <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
+        <exception cref="T:System.InvalidOperationException">The request message was already sent by the <see cref="T:System.Net.Http.HttpClient" /> instance.</exception>
+        <exception cref="T:System.Net.Http.HttpRequestException">The request failed due to an underlying issue such as network connectivity, DNS failure, or server certificate validation.</exception>
+        <exception cref="T:System.Threading.Tasks.TaskCanceledException">If the <see cref="T:System.Threading.Tasks.TaskCanceledException" /> exception nests the <see cref="T:System.TimeoutException" />:
+ The request failed due to timeout.</exception>
       </Docs>
     </Member>
     <Member MemberName="Send">
@@ -2715,11 +2736,32 @@ The <paramref name="requestUri" /> is not an absolute URI.
         <Parameter Name="completionOption" Type="System.Net.Http.HttpCompletionOption" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="completionOption">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="completionOption">One of the enumeration values that specifies when the operation should complete (as soon as a response is available or after reading the response content).</param>
+        <summary>Sends an HTTP request.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+  
+## Remarks  
+ This operation blocks until the entire response, including content, is read.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">The HTTP version is 2.0 or higher or the version policy is set to <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ The custom class derived from <see cref="T:System.Net.Http.HttpContent" /> does not override the <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+The custom <see cref="T:System.Net.Http.HttpMessageHandler" /> does not override the <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
+        <exception cref="T:System.InvalidOperationException">The request message was already sent by the <see cref="T:System.Net.Http.HttpClient" /> instance.</exception>
+        <exception cref="T:System.Net.Http.HttpRequestException">The request failed due to an underlying issue such as network connectivity, DNS failure, or server certificate validation.</exception>
+        <exception cref="T:System.Threading.Tasks.TaskCanceledException">If the <see cref="T:System.Threading.Tasks.TaskCanceledException" /> exception nests the <see cref="T:System.TimeoutException" />:
+ The request failed due to timeout.</exception>
       </Docs>
     </Member>
     <Member MemberName="Send">
@@ -2745,11 +2787,36 @@ The <paramref name="requestUri" /> is not an absolute URI.
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="cancellationToken">The token to cancel the operation.</param>
+        <summary>Sends an HTTP request with the specified request and cancellation token.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ This operation blocks until the entire response, including content, is read or `cancellationToken` cancels the operation.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">The HTTP version is 2.0 or higher or the version policy is set to <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ The custom class derived from <see cref="T:System.Net.Http.HttpContent" /> does not override the <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+The custom <see cref="T:System.Net.Http.HttpMessageHandler" /> does not override the <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
+        <exception cref="T:System.InvalidOperationException">The request message was already sent by the <see cref="T:System.Net.Http.HttpClient" /> instance.</exception>
+        <exception cref="T:System.Net.Http.HttpRequestException">The request failed due to an underlying issue such as network connectivity, DNS failure, or server certificate validation.</exception>
+        <exception cref="T:System.Threading.Tasks.TaskCanceledException">The request was canceled.
+
+ -or-
+
+ If the <see cref="T:System.Threading.Tasks.TaskCanceledException" /> exception nests the <see cref="T:System.TimeoutException" />:
+ The request failed due to timeout.</exception>
       </Docs>
     </Member>
     <Member MemberName="Send">
@@ -2776,12 +2843,37 @@ The <paramref name="requestUri" /> is not an absolute URI.
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="completionOption">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="completionOption">One of the enumeration values that specifies when the operation should complete (as soon as a response is available or after reading the response content).</param>
+        <param name="cancellationToken">The token to cancel the operation.</param>
+        <summary>Sends an HTTP request with the specified request, completion option and cancellation token.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ This operation blocks until the entire response, including content, is read or `cancellationToken` cancels the operation.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> is <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">The HTTP version is 2.0 or higher or the version policy is set to <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ The custom class derived from <see cref="T:System.Net.Http.HttpContent" /> does not override the <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+The custom <see cref="T:System.Net.Http.HttpMessageHandler" /> does not override the <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
+        <exception cref="T:System.InvalidOperationException">The request message was already sent by the <see cref="T:System.Net.Http.HttpClient" /> instance.</exception>
+        <exception cref="T:System.Net.Http.HttpRequestException">The request failed due to an underlying issue such as network connectivity, DNS failure, or server certificate validation.</exception>
+        <exception cref="T:System.Threading.Tasks.TaskCanceledException">The request was canceled.
+
+ -or-
+
+ If the <see cref="T:System.Threading.Tasks.TaskCanceledException" /> exception nests the <see cref="T:System.TimeoutException" />:
+ The request failed due to timeout.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="SendAsync">
diff --git a/xml/System.Net.Http/HttpClientHandler.xml b/xml/System.Net.Http/HttpClientHandler.xml
index 1b6173d528e..9ed244df9f7 100644
--- a/xml/System.Net.Http/HttpClientHandler.xml
+++ b/xml/System.Net.Http/HttpClientHandler.xml
@@ -828,11 +828,34 @@ handler.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousA
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message.</param>
+        <param name="cancellationToken">A cancellation token to cancel the operation.</param>
+        <summary>Creates an instance of  <see cref="T:System.Net.Http.HttpResponseMessage" /> based on the information provided in the <see cref="T:System.Net.Http.HttpRequestMessage" />.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+ This operation blocks until the response message is read.
+
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> was <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">For HTTP/2 and higher or when requesting version upgrade is enabled by <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ If using custom class derived from <see cref="T:System.Net.Http.HttpContent" /> not overriding <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+ If using custom <see cref="T:System.Net.Http.HttpMessageHandler" /> not overriding <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
+        <exception cref="T:System.Threading.Tasks.TaskCanceledException">The request was canceled.
+
+ -or-
+
+ If the <see cref="T:System.Threading.Tasks.TaskCanceledException" /> exception nests the <see cref="T:System.TimeoutException" />:
+ The request failed due to timeout.</exception>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/HttpContent.xml b/xml/System.Net.Http/HttpContent.xml
index b7f25ab9047..db44e5b6157 100644
--- a/xml/System.Net.Http/HttpContent.xml
+++ b/xml/System.Net.Http/HttpContent.xml
@@ -88,11 +88,19 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Information about the transport (for example, the channel binding token). This parameter may be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Serializes the HTTP content into a stream of bytes and copies it to <paramref name="stream" />.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+  
+## Remarks
+This operation blocks until all of the content is written to the stream object.
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="stream" /> was <see langword="null" />.</exception>
       </Docs>
     </Member>
     <MemberGroup MemberName="CopyToAsync">
@@ -737,9 +745,16 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <summary>Serializes the HTTP content and returns a stream that represents the content.</summary>
+        <returns>The stream that represents the HTTP content.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the stream that represents content has been read.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="ReadAsStream">
@@ -764,10 +779,17 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="0" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Serializes the HTTP content and returns a stream that represents the content.</summary>
+        <returns>The stream that represents the HTTP content.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the stream that represents content has been read.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="ReadAsStreamAsync">
@@ -964,11 +986,19 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Information about the transport (for example, the channel binding token). This parameter may be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>When overridden in a derived class, serializes the HTTP content to a stream. Otherwise, throws a <see cref="T:System.NotImplementedException" />.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the content has been serialized to the stream object.  
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.NotImplementedException">The method is not overridden in the derived class.</exception>
       </Docs>
     </Member>
     <Member MemberName="SerializeToStreamAsync">
diff --git a/xml/System.Net.Http/HttpMessageHandler.xml b/xml/System.Net.Http/HttpMessageHandler.xml
index 4f730e0a0e9..3f9176205a6 100644
--- a/xml/System.Net.Http/HttpMessageHandler.xml
+++ b/xml/System.Net.Http/HttpMessageHandler.xml
@@ -196,11 +196,12 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="cancellationToken">The cancellation token to cancel operation.</param>
+        <summary>When overridden in a derived class, sends an HTTP request with the specified request and cancellation token. Otherwise, throws a <see cref="T:System.NotImplementedException" />.</summary>
+        <returns>The HTTP response message.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.NotImplementedException">The method is not overridden in the derived class.</exception>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/HttpMessageInvoker.xml b/xml/System.Net.Http/HttpMessageInvoker.xml
index 90ed3048543..92586fbff04 100644
--- a/xml/System.Net.Http/HttpMessageInvoker.xml
+++ b/xml/System.Net.Http/HttpMessageInvoker.xml
@@ -230,11 +230,30 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="cancellationToken">The cancellation token to cancel operation.</param>
+        <summary>Sends an HTTP request with the specified request and cancellation token.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until the entire response, including content, is read.
+  
+ Most applications that are connecting to a web site will use one of the <xref:System.Net.Http.HttpClient.Send%2A> or <xref:System.Net.Http.HttpClient.SendAsync%2A> methods on the <xref:System.Net.Http.HttpClient> class.  
+  
+ ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException">The <paramref name="request" /> was <see langword="null" />.</exception>
+        <exception cref="T:System.NotSupportedException">For HTTP/2 and higher or when requesting version upgrade is enabled by <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ If using custom class derived from <see cref="T:System.Net.Http.HttpContent" /> not overriding <see cref="M:System.Net.Http.HttpContent.SerializeToStream(System.IO.Stream,System.Net.TransportContext,System.Threading.CancellationToken)" /> method.
+
+ -or-
+
+ If using custom <see cref="T:System.Net.Http.HttpMessageHandler" /> not overriding <see cref="M:System.Net.Http.HttpMessageHandler.Send(System.Net.Http.HttpRequestMessage,System.Threading.CancellationToken)" /> method.</exception>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/MessageProcessingHandler.xml b/xml/System.Net.Http/MessageProcessingHandler.xml
index e39716b183d..251fe4ea6fd 100644
--- a/xml/System.Net.Http/MessageProcessingHandler.xml
+++ b/xml/System.Net.Http/MessageProcessingHandler.xml
@@ -226,11 +226,18 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="request">The HTTP request message to send to the server.</param>
+        <param name="cancellationToken">A cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
+        <summary>Sends an HTTP request to the inner handler to send to the server.</summary>
+        <returns>The HTTP response message.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until the entire response, including content, is read, or until `cancellationToken` cancels the operation.
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/MultipartContent.xml b/xml/System.Net.Http/MultipartContent.xml
index 2aee3a22cb0..2b29c753104 100644
--- a/xml/System.Net.Http/MultipartContent.xml
+++ b/xml/System.Net.Http/MultipartContent.xml
@@ -212,10 +212,19 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="0" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Serializes the HTTP content to a stream using the multipart/* encoding.</summary>
+        <returns>The HTTP content stream that represents the multipart/* encoded HTTP content.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This method overrides <xref:System.Net.Http.HttpContent.CreateContentReadStream%2A?displayProperty=nameWithType> to use a custom stream that contains an array, with each HTTP content entity and its boundary encoded and serialized to a <xref:System.IO.MemoryStream> instance.
+
+This operation blocks until all of the content has been written to the memory stream.   
+    
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="CreateContentReadStreamAsync">
@@ -434,11 +443,18 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Information about the transport (for example, the channel binding token). This parameter may be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>    
+        <summary>Serializes the multipart HTTP content to a stream.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+ This operation blocks untill all of the content has been serialized to the stream object passed in the `stream` parameter.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SerializeToStreamAsync">
diff --git a/xml/System.Net.Http/ReadOnlyMemoryContent.xml b/xml/System.Net.Http/ReadOnlyMemoryContent.xml
index 6741e9496ae..2f57c60c4b9 100644
--- a/xml/System.Net.Http/ReadOnlyMemoryContent.xml
+++ b/xml/System.Net.Http/ReadOnlyMemoryContent.xml
@@ -134,11 +134,18 @@
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Information about the transport (for example, the channel binding token). This parameter may be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>    
+        <summary>Serializes the multipart HTTP content to a stream.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the content has been serialized to the stream object passed as the `stream` parameter.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SerializeToStreamAsync">
diff --git a/xml/System.Net.Http/SocketsHttpHandler.xml b/xml/System.Net.Http/SocketsHttpHandler.xml
index e9e0700fdd4..3b11c0f6950 100644
--- a/xml/System.Net.Http/SocketsHttpHandler.xml
+++ b/xml/System.Net.Http/SocketsHttpHandler.xml
@@ -740,11 +740,20 @@ Draining occurs when a request is cancelled or a response is disposed prior to f
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="1" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="request">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="request">The HTTP request message to send.</param>
+        <param name="cancellationToken">The cancellation token.</param>
+        <summary>Sends an HTTP request.</summary>
+        <returns>The HTTP response message.</returns>
         <remarks>To be added.</remarks>
+<exception cref="T:System.NotSupportedException">For HTTP/2 and higher or when requesting version upgrade is enabled by <see cref="F:System.Net.Http.HttpVersionPolicy.RequestVersionOrHigher" />.
+
+ -or-
+
+ If using custom class derived from <see cref="T:System.Net.Http.HttpContent" /> not overriding <see cref="T:System.Net.Http.SerializeToStream" /> method.
+
+ -or-
+
+ If using custom <see cref="T:System.Net.Http.HttpMessageHandler" /> not overriding <see cref="T:System.Net.Http.HttpMessageHandler.Send" /> method.</exception>
       </Docs>
     </Member>
     <Member MemberName="SendAsync">
diff --git a/xml/System.Net.Http/StreamContent.xml b/xml/System.Net.Http/StreamContent.xml
index fb2ecd95a90..c49823b033e 100644
--- a/xml/System.Net.Http/StreamContent.xml
+++ b/xml/System.Net.Http/StreamContent.xml
@@ -149,10 +149,19 @@ The <xref:System.Net.Http.StreamContent> object calls <xref:System.IO.Stream.Dis
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="0" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>
+        <summary>Writes the HTTP stream content to a memory stream.</summary>
+        <returns>The HTTP content stream.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the content has been written to the memory stream.
+  
+ The <xref:System.Net.Http.StreamContent.CreateContentReadStream%2A> method buffers the content to a memory stream. Derived classes can override this behavior if there's a better way to retrieve the content as stream. For example, a byte array or a string could use a more efficient mechanism, such as wrapping a read-only <xref:System.IO.MemoryStream> around the bytes or string.
+  
+ ]]></format>        
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="CreateContentReadStreamAsync">
@@ -264,11 +273,18 @@ The <xref:System.Net.Http.StreamContent> object calls <xref:System.IO.Stream.Dis
         <Parameter Name="cancellationToken" Type="System.Threading.CancellationToken" Index="2" FrameworkAlternate="net-5.0" />
       </Parameters>
       <Docs>
-        <param name="stream">To be added.</param>
-        <param name="context">To be added.</param>
-        <param name="cancellationToken">To be added.</param>
-        <summary>To be added.</summary>
-        <remarks>To be added.</remarks>
+        <param name="stream">The target stream.</param>
+        <param name="context">Information about the transport (for example, the channel binding token). This parameter may be <see langword="null" />.</param>
+        <param name="cancellationToken">The cancellation token to cancel the operation.</param>    
+        <summary>Serializes the multipart HTTP content to a stream.</summary>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+This operation blocks until all of the content has been serialized to the stream object passed as the `stream` parameter.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="SerializeToStreamAsync">