How do I know if Shared Contacts Manager is installed domain-wide?

To check if a Google Workspace app is installed domain-wide, you should follow these steps:

1. Sign in to Google Admin Console and log in with your admin credentials.

2. From the Admin Console Home page, go to Apps.

3. Click on Apps list to view all installed applications. 

4. Check the installation status. Look for the app you want to check out.

If the app is listed here, it is installed domain-wide. You can click on the app for more details about its installation and settings.