When logging in to a service, you'll need to open the app and look at a 6-digit code that is displayed in the app. This option is a good choice when there is no access to cellular data or WIFI, and you need to log into a service (ex: airplanes).





The Mobile verification code is added by default after you add the authenticator app as an option for verification. You'll just need to set it as the "Default sign-in method"
