Two-factor authentication
Two-factor authentication asks for a code from an authenticator app each time you log in.
Go to Account, then Security, and choose Enable next to Two-factor authentication. We email you a code to confirm it's you. Then scan the code on screen with an authenticator app, such as Google Authenticator, 1Password or Authy, and enter the 6-digit code it shows.
Save your backup codes somewhere safe. Each one works once if you lose your authenticator, and you won't see them again.
To turn it off, choose Disable and enter a code from your app or a backup code.