2FA allows you to do is to secure your account from hacking, by utilizing a 2nd sign-in code that exists on your smart phone. When you log in you will be prompted to enter a code, which is on an app on your phone. This is the 2nd factor in 2 factor- the first being your password. This code on the phone is time sensitive, and will expire.
With 2FA, even if someone hacks your computer, they can't get into your account unless they also get access to the 2nd device, your phone. To use this feature, you will need a 2fa app, like google authenticator or authy.