Two-factor authentication

Two-factor authentication (2FA; sometimes also called multi-factor authentication) is a method of confirming a user's claimed identity by utilizing a combination of two different components.

You are probably looking for one of these:

• 2FA on Wikimedia wikis:
  • m:Help:Two-factor authentication
  • Developer documentation: the main MediaWiki extension that provides 2FA functionality is OATHAuth.
  • Password and 2FA reset#Reset two factor authentication
• 2FA for Phabricator accounts:
  • User Guide: Multi-Factor Authentication
  • Phabricator#Removing Two Factor Authentication
• 2FA for Wikimedia developer accounts:
  • Single Sign On#Enabling 2FA using a YubiKey
  • CAS-SSO#Enabling U2F as a second factor
• Using 2FA on your own machine to secure Wikimedia production credentials
  • Yubikey-SSH
  • Yubikey-SSH-FIDO
  • Yubikey4 and gpg-agent
• Whatever this is
  • Yubikey-2FA