by WordPress.org on WordPress.org
Enable Two-Factor Authentication (2FA) using time-based one-time passwords (TOTP), Universal 2nd Factor (U2F), email, and backup verification codes.

Two-factor options under User Profile - Shows the main configuration area where users can enable different authentication methods.
The Two-Factor plugin adds an extra layer of security to your WordPress login by requiring users to provide a second form of authentication in addition to their password. This helps protect against unauthorized access even if passwords are compromised.
Important: Each user must individually configure their two-factor authentication settings. There are no site-wide settings for this plugin.
For more information about two-factor authentication in WordPress, see the WordPress Advanced Administration Security Guide.
For more history, see this post.
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_user_api_login_enable filter restricts authentication for REST API and XML-RPC to application passwords only. Provides the user ID as the second argument.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. Provides the WP_User of the associated user as the second argument.two_factor_rest_api_can_edit_user filter overrides whether a user’s Two-Factor settings can be edited via the REST API. First argument is the current $can_edit boolean, the second argument is the user ID.two_factor_before_authentication_prompt action which receives the provider object and fires prior to the prompt shown on the authentication input form.two_factor_after_authentication_prompt action which receives the provider object and fires after the prompt shown on the authentication input form.two_factor_after_authentication_inputaction which receives the provider object and fires after the input shown on the authentication input form (if form contains no input, action fires immediately after two_factor_after_authentication_prompt).