How to enable Google Authenticator system for your WordPress site
The Google Authenticator two-factor authentication helps your site users to add Google Authenticator to their WordPress user profile.
Note: This is optional and can't be enforced.
The Google Authenticator system can be enabled under the Login Protection > 2FA: OTP:
When this system is enabled, users will have the option to add Google Authenticator to their WordPress user profile.
Important: This enables the functionality, but it must be then in-turn configured for each individual user who wishes enable it for their own account.
To learn how to enable Google Authenticator for your WordPress user account, read the article here.