How to Set up Two-Factor Authentication for Firefox
Firefox has begun rolling out two-factor authentication, and if you use your browser to store passwords, you should enable it now.
If you are not familiar with two-factor authentication, it essentially acts as a second line of defense for your account. When you enter your password, you will also be prompted to enter a numeric code that you will receive from the Authenticator app (some sites and services also allow you to receive this number via SMS). This means that the fraudster will not only need to get your password to log into your account, but also your phone.
Two-factor mode is currently being rolled out and should soon be available in your Firefox browser’s settings menu. If you don’t want to wait (shouldn’t), you can also enable it now by clicking this link and then clicking “Enable” next to the 2-Step Verification menu item. When you do, a QR code will appear that you can scan to connect your account to the Authenticator app.
This means you need to select the Authenticator app for it to work. I personally recommend Google Authenticator or Authy .