Improve Apple app specific password docs (#169)

apple-app-specific-password.md

@@ -1,6 +1,6 @@
 # Apple App-Specific Password
 
-The Apple app-specific password is a password for your Apple ID account that lets you sign in to your Apple account securely from a third-party app. It is required by the EAS Submission Service to submit your build to Apple App Store.
+The Apple app-specific password is a password for your Apple ID account that lets you sign in to your Apple account securely from a third-party app. It is required by the EAS Submission Service to submit your build to the Apple App Store.
 
 ### How do I generate an app-specific password?
 
@@ -11,3 +11,14 @@ The Apple app-specific password is a password for your Apple ID account that let
 > **Important note**: To generate and use app-specific passwords, your Apple ID must be protected with [two-factor authentication](https://support.apple.com/kb/HT204915) (2FA).
 
 You can learn more about app-specific passwords [here](https://support.apple.com/en-us/HT204397).
+
+## How do I use the app-specific password once I have generated it?
+
+You can use [EAS CLI](https://github.com/expo/eas-cli) to submit your build to the Apple App Store using the app-specific password.
+The app-specific password is passed to the EAS CLI as an environment variable called `EXPO_APPLE_APP_SPECIFIC_PASSWORD`.
+
+Use the following command to submit your iOS build using the app-specific password:
+
+```bash
+EXPO_APPLE_APP_SPECIFIC_PASSWORD=your_app_specific_password eas submit -p ios
+```