Multi-Factor Authentication (MFA) requires you to identify yourself with not one, but two factors. Your user ID and password count as one form of authentication. If you have already used your computer and browser to login to online banking, the computer serves as your second factor because it has a stored cookie file. Similarly once you log in to your mobile app with MFA, your app will serve as the second factor of authorization for logins moving forward. However If you visit online banking using a machine without this cookie file, have your browser set to automatically clear cookies or login to your mobile app on a new device, it generates a Verification Code and sends it to you via a method that only you would have access to read, such as your mobile phone (via text) or personal email.