I just followed How to configure your App Service application to use Google login to configure my App Service Authentication (Easy Auth) for Google login. I just leverage the Server-managed authentication and log with my mobile app backend via the browser as follows:
GET https://<your-app-name>.azurewebsites.net/.auth/login/google
Using fiddler to capture the network traces as follows:

Then, access the /.auth/me
endpoint via the browser, I could retrieve the user email as follows:

Moreover, you could follow Obtaining user profile information. Also, you could access https://www.googleapis.com/oauth2/v1/userinfo?access_token=<access_token>
to retrieve the user profile manually.
Additionally, if you want to modify the google OAuth Scopes (set googleOAuthScopes
array property via https://resources.azure.com
) or retrieve the refresh token (access_type=offline), you could follow this similar issue. And you could follow App Service Token Store for more details about App Service Authentication.