by David Anderson / Team Updraft on WordPress.org
Secure WordPress login with Two Factor Authentication - supports WP, Woo + other login forms, HOTP, TOTP (Google Authenticator, Authy, etc.)

Site-wide settings
Secure WordPress login with this two factor authentication (TFA / 2FA) plugin. Users for whom it is enabled will require a one-time code in order to log in. From the authors of UpdraftPlus – WP’s #1 backup/restore plugin, with over two million active installs.
Are you completely new to TFA? If so, please see our FAQ.
Features (please see the “Screenshots” for more information):
Read this! https://www.wired.com/2012/08/apple-amazon-mat-honan-hacking/
This plugin uses the industry standard TFA / 2FA algorithm TOTP or HOTP for creating One Time Passwords. These are used by Google Authenticator, Authy, and many other OTP applications that you can deploy on your phone etc.
A TOTP code is valid for a certain time. Whatever program you use (i.e. Google Authenticator, etc.) will show a different code every so often.
This plugin began life in early 2015 as a friendly fork and enhancement of Oscar Hane’s “two factor auth” plugin.