Fortnite Two factor authentication, 2FA, or multifactor authentication makes your account more secure by requiring a second layer of authentication. The way it works is that whenever the game detects a login from a new machine it will ask for proof it's you in one of two ways. You'll either be asked for a code sent only to the account holder via email, or be asked for a code from an authenticator app like Google Authenticator, LastPass Authenticator, Microsoft Authenticator or Authy. It means your account will be completely secure against hacks and password leaks.