diff --git a/xml/System.IO/WindowsRuntimeStorageExtensions.xml b/xml/System.IO/WindowsRuntimeStorageExtensions.xml
index f5cdf0c6436..0e3aca8be59 100644
--- a/xml/System.IO/WindowsRuntimeStorageExtensions.xml
+++ b/xml/System.IO/WindowsRuntimeStorageExtensions.xml
@@ -52,6 +52,28 @@ The next example shows the XAML code that is associated with the previous exampl
     </remarks>
   </Docs>
   <Members>
+    <MemberGroup MemberName="CreateSafeFileHandle">
+      <AssemblyInfo>
+        <AssemblyName>System.Runtime.WindowsRuntime</AssemblyName>
+        <AssemblyVersion>4.0.14.0</AssemblyVersion>
+      </AssemblyInfo>
+      <Docs>
+        <summary>Creates and returns a reference to a safe file handle for the IStorage instance that is being extended.</summary>
+        <remarks>
+          <format type="text/markdown">
+            <![CDATA[
+
+## Remarks
+
+With the Windows 10 Anniversary Update, new interfaces were added to <xref:Windows.Storage.IStorageFolder> and <xref:Windows.Storage.IStorageFile> that allow creating a standard Win32 file handle: `IStorageFolderHandleAccess` and `IStorageItemHandleAccess`. The `CreateSafeFileHandle` group of extension methods take advantage of the `Create` methods of these interfaces.
+
+The key benefit of the API is access to a brokered `SafeFileHandle`. This is critically important if you want to create a <xref:System.IO.FileStream> around an <xref:Windows.Storage.IStorageItem> or <xref:Windows.Storage.IStorageFolder> when you are running in an [AppContainer](https://docs.microsoft.com/en-us/windows/win32/secauthz/appcontainer-isolation). When running in an AppContainer, the application has very limited file access rights. Things like picture and document folders require the native file handle to be proxied via `RuntimeBroker.exe`, as the application process itself doesn't have rights to most files. This API gets the proxied handle. If accessing user data folders or using a file picker, this API should always be used to create <xref:System.IO.FileStream>. Using a path will often throw <xref:System.AccessViolationException> in these cases.
+
+          ]]>
+          </format>
+        </remarks>
+      </Docs>
+    </MemberGroup>
     <Member MemberName="CreateSafeFileHandle">
       <MemberSignature Language="C#" Value="public static Microsoft.Win32.SafeHandles.SafeFileHandle CreateSafeFileHandle (this Windows.Storage.IStorageFolder rootDirectory, string relativePath, System.IO.FileMode mode);" />
       <MemberSignature Language="ILAsm" Value=".method public static hidebysig class Microsoft.Win32.SafeHandles.SafeFileHandle CreateSafeFileHandle(class Windows.Storage.IStorageFolder rootDirectory, string relativePath, valuetype System.IO.FileMode mode) cil managed" />
@@ -78,12 +100,27 @@ The next example shows the XAML code that is associated with the previous exampl
         <Parameter Name="mode" Type="System.IO.FileMode" Index="2" FrameworkAlternate="dotnet-plat-ext-3.0" />
       </Parameters>
       <Docs>
-        <param name="rootDirectory">To be added.</param>
-        <param name="relativePath">To be added.</param>
-        <param name="mode">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
-        <remarks>To be added.</remarks>
+        <param name="rootDirectory">The current storage folder instance.</param>
+        <param name="relativePath">The name of the file that you want to get a handle to.</param>
+        <param name="mode">The mode in which the operating system should open the file.</param>
+        <summary>Creates a safe file handle for a file that is in the current storage folder instance.</summary>
+        <returns>A safe file handle instance if the operation succeeds; <see langword="null" /> if the conversion of the <paramref name="rootDirectory" /> to an IStorageFolderHandleAccess returns <see langword="null" />.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+When calling this method, if the specified mode is <xref:System.IO.FileMode.Append?displayProperty=nameWithType>, the file will be opened with <xref:System.IO.FileAccess.Read?displayProperty=nameWithType> access permission. For any other modes, the file will be opened with <xref:System.IO.FileAccess.ReadWrite?displayProperty=nameWithType> access permission.
+
+Additionally, this method will open the file with <xref:System.IO.FileShare.Read?displayProperty=nameWithType> stream sharing access and with <xref:System.IO.FileOptions.None?displayProperty=nameWithType> advanced file creation options.
+
+          ]]></format>
+        </remarks>
+        <exception cref="T:System.ArgumentNullException"><paramref name="rootDirectory" /> is <see langword="null" />.
+
+ -or-
+
+<paramref name="relativePath" /> is <see langword="null" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="CreateSafeFileHandle">
@@ -112,13 +149,14 @@ The next example shows the XAML code that is associated with the previous exampl
         <Parameter Name="options" Type="System.IO.FileOptions" Index="3" FrameworkAlternate="dotnet-plat-ext-3.0" />
       </Parameters>
       <Docs>
-        <param name="windowsRuntimeFile">To be added.</param>
-        <param name="access">To be added.</param>
-        <param name="share">To be added.</param>
-        <param name="options">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="windowsRuntimeFile">A storage file instance.</param>
+        <param name="access">The kind of access that should be used when opening the file. The default value is <see cref="F:System.IO.FileAccess.ReadWrite" />.</param>
+        <param name="share">The kind of stream sharing access other <see cref="T:System.IO.FileStream" /> objects can have to the same file. The default value is <see cref="F:System.IO.FileShare.Read" />.</param>
+        <param name="options">Advanced options for creating the <see cref="T:System.IO.FileStream" /> object. The default value is <see cref="F:System.IO.FileOptions.None" />.</param>
+        <summary>Creates a safe file handle for a the current storage file instance.</summary>
+        <returns>A safe file handle instance if the operation succeeds; <see langword="null" /> if the conversion of the <paramref name="windowsRuntimeFile" /> to an IStorageItemHandleAccess returns <see langword="null" />.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException"><paramref name="windowsRuntimeFile" /> is <see langword="null" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="CreateSafeFileHandle">
@@ -149,15 +187,20 @@ The next example shows the XAML code that is associated with the previous exampl
         <Parameter Name="options" Type="System.IO.FileOptions" Index="5" FrameworkAlternate="dotnet-plat-ext-3.0" />
       </Parameters>
       <Docs>
-        <param name="rootDirectory">To be added.</param>
-        <param name="relativePath">To be added.</param>
-        <param name="mode">To be added.</param>
-        <param name="access">To be added.</param>
-        <param name="share">To be added.</param>
-        <param name="options">To be added.</param>
-        <summary>To be added.</summary>
-        <returns>To be added.</returns>
+        <param name="rootDirectory">The current storage folder instance.</param>
+        <param name="relativePath">The name of the file that you want to get a handle to.</param>
+        <param name="mode">The mode in which the operating system should open the file.</param>
+        <param name="access">The kind of access that should be used when opening the file.</param>
+        <param name="share">The kind of stream sharing access other <see cref="T:System.IO.FileStream" /> objects can have to the same file. The default value is <see cref="F:System.IO.FileShare.Read" />.</param>
+        <param name="options">Advanced options for creating the <see cref="T:System.IO.FileStream" /> object. The default value is <see cref="F:System.IO.FileOptions.None" />.</param>
+        <summary>Creates a safe file handle for a file that is in the current storage folder instance.</summary>
+        <returns>A safe file handle instance if the operation succeeds; <see langword="null" /> if the conversion of the <paramref name="rootDirectory" /> to an IStorageFolderHandleAccess returns <see langword="null" />.</returns>
         <remarks>To be added.</remarks>
+        <exception cref="T:System.ArgumentNullException"><paramref name="rootDirectory" /> is <see langword="null" />.
+
+ -or-
+
+<paramref name="relativePath" /> is <see langword="null" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="OpenStreamForReadAsync">
@@ -384,4 +427,4 @@ The next example shows the XAML code that is associated with the previous exampl
       </Docs>
     </Member>
   </Members>
-</Type>
\ No newline at end of file
+</Type>