MFA

Multi-factor, or two-factor, means being asked for more than one thing before you get in. Normally something you know, like a password, plus something you have, like your phone.

The point is that a stolen password on its own is no longer enough, and stolen passwords are how most accounts get taken. It is not a guarantee, and the methods are not all as good as each other. A code texted to you can be intercepted, or talked out of you by somebody convincing on the phone. A small key that plugs into your computer cannot be fooled the same way, because it checks the website's real address before it answers. If you get a choice, that is the one worth having.