Update windows x64 doc

docs-ref-conceptual/install-azure-cli-windows.md

@@ -36,11 +36,12 @@ The MSI distributable is used for installing or updating the Azure CLI on Window
 Download and install the latest release of the Azure CLI. When the installer asks if it can make changes to your computer, click the "Yes" box.
 
 > [!div class="nextstepaction"]
-> [Latest release of the Azure CLI](https://aka.ms/installazurecliwindows)
+> [Latest release of the Azure CLI (32-bit)](https://aka.ms/installazurecliwindows)
+> [Latest release of the Azure CLI (64-bit)](https://aka.ms/installazurecliwindowsx64)
 
 ### Specific version
 
-To download the MSI installer for specific version, change the version segment in URL `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>.msi` and download it. Available versions can be found at [Azure CLI release notes](./release-notes-azure-cli.md).
+To download the MSI installer for specific version, change the version segment in URL `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>.msi` (32-bit) or `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>-x64.msi` (64-bit) and download it. Available versions can be found at [Azure CLI release notes](./release-notes-azure-cli.md). (64-bit MSI is available from 2.51.0.)
 
 # [Microsoft Installer (MSI) with Command](#tab/powershell)
 
@@ -58,9 +59,9 @@ To install the Azure CLI using PowerShell, start PowerShell **as administrator**
    $ProgressPreference = 'SilentlyContinue'; Invoke-WebRequest -Uri https://aka.ms/installazurecliwindows -OutFile .\AzureCLI.msi; Start-Process msiexec.exe -Wait -ArgumentList '/I AzureCLI.msi /quiet'; Remove-Item .\AzureCLI.msi
    ```
 
-This will download and install the latest version of the Azure CLI for Windows. If you already have a version installed, the installer will update the existing version.
+This will download and install the latest 32-bit version of the Azure CLI for Windows. If you prefer 64-bit one, please change URL to `https://aka.ms/installazurecliwindowsx64`. If you already have a version installed, the installer will update the existing version.
 
-To install specific version, replace the `-Uri` argument with `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>.msi` with version segment changed. Available versions can be found at [Azure CLI release notes](./release-notes-azure-cli.md).
+To install specific version, replace the `-Uri` argument with `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>.msi` (32-bit) or `https://azcliprod.blob.core.windows.net/msi/azure-cli-<version>-x64.msi` (64-bit) with version segment changed. Available versions can be found at [Azure CLI release notes](./release-notes-azure-cli.md). (64-bit MSI is available from 2.51.0.)
 
 ### Azure CLI Command (for update only)
 
@@ -144,6 +145,18 @@ In order to get the MSI, your proxy needs to allow HTTPS connections to the foll
 * `https://aka.ms/`
 * `https://azcliprod.blob.core.windows.net/`
 
+### Migrate to 64-bit Azure CLI
+
+Starting from 2.51.0, Azure CLI also provides 64-bit MSI which is recommended for better performance.
+
+If you are using 32-bit version, you can migrate to 64-bit version by following these steps:
+1. Check your current CLI version and installed extensions by running `az --version`.
+2. If the extension folder `%userprofile%\.azure\cliextensions` exists, make a backup by renaming it. This folder will be created again after migration.
+3. Download and install latest 64-bit version following the [Install or update](#install-or-update) guide. Please note that 32-bit MSI will be uninstalled automatically.
+4. Install extensions by running `az extension add --name <extension> --version <version>`.
+
+If you have issues after migration, you can uninstall the 64-bit MSI and reinstall the 32-bit MSI.  If you have made a backup of your 32-bit extension folder, restore your extension folder after the change.
+
 ## Uninstall
 
 [!INCLUDE [uninstall-boilerplate.md](includes/uninstall-boilerplate.md)]