1) Open the Desktop.com app
2) Navigate to the Apps section and click the Add app button
3) Click the Create custom app button on the bottom left
4) Now you need to make your custom app URL looks like: https://mail.google.com/a/[your-bussiness-domain] . Where [your-business-domain] should be replaced with your actual domain address.
For example, if your Google Workspace address is: firstname.lastname@example.org
URL for the custom app should look like:
After you entered the app name, your custom app URL and chosen a category, click the Add application button
5) Now your Google Workspace has been created as the custom app and you can add this to your desktop