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 main Security Zones navigation menu. When you click gear icon next to Login zone to edit settings for this entire Zone, a configuration sidebar window will open up for you. Then, select 2FA: OTP tab.
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.