Two-factor authentication is a security feature that helps protect your Facebook account in addition to your password. If you set up two-factor authentication, you’ll be asked to enter a special login code or confirm your login attempt each time someone tries accessing Facebook from a browser or mobile device that we don’t recognise. You can also get alerts when someone tries logging in from a browser or mobile device that we don’t recognise.
If you haven’t saved the browser or mobile device that you’re using, you’ll be asked to do so when you turn on two-factor authentication. This way, you won’t have to enter a security code when you log in again. Don’t click Save this browser if you’re using a public computer that other people can access (e.g. a library computer).
We need to be able to remember your computer and browser information so that we can recognise it the next time you log in. Some browser features block this. If you’ve turned on private browsing or set up your browser to clear your history every time it closes, you might have to enter a code every time you log in. Learn more.
To set up text message (SMS) two-factor authentication, you can either use a mobile number that’s already been added to your account or add a new number. Learn more about how Facebook uses a mobile number added for two-factor authentication.