Use the “Two-Factor Options” section under “Users” → “Your Profile” to enable and configure one or multiple two-factor authentication providers for your account:

• Email codes
• Time Based One-Time Passwords (TOTP)
• FIDO Universal 2nd Factor (U2F)
• Backup Codes
• Dummy Method (only for testing purposes)

For more history, see this post.

Actions & Filters

Here is a list of action and filter hooks provided by the plugin:

• two_factor_providers filter overrides the available two-factor providers such as email and time-based one-time passwords. Array values are PHP classnames of the two-factor providers.
• two_factor_providers_for_user filter overrides the available two-factor providers for a specific user. Array values are instances of provider classes and the user object WP_User is available as the second argument.
• two_factor_enabled_providers_for_user filter overrides the list of two-factor providers enabled for a user. First argument is an array of enabled provider classnames as values, the second argument is the user ID.
• two_factor_user_authenticated action which receives the logged in WP_User object as the first argument for determining the logged in user right after the authentication workflow.
• two_factor_email_token_ttl filter overrides the time interval in seconds that an email token is considered after generation. Accepts the time in seconds as the first argument and the ID of the WP_User object being authenticated.
• two_factor_email_token_length filter overrides the default 8 character count for email tokens.
• two_factor_backup_code_length filter overrides the default 8 character count for backup codes. Providers the WP_User of the associated user as the second argument.