Enable 2-Step Verification for your domain
In your Google Admin console (at admin.google.com)...
- Click Security > Basic settings.
Where is it?
- Under 2-Step Verification, check Allow users to turn on 2-step verification.
This makes 2-Step Verification available for your users, but does not automatically enroll them. To enroll, users need to configure their verification settings individually. See Turn on 2-Step Verification.
Once all users have enrolled in 2-Step Verification, you can enforce its use following the instructions in Enforcement.