Your Facebook account can be protected with two-factor authentication (2FA). This means that you add an extra layer of security to your Facebook account. For the second step, you can use Nexus Personal Mobile, which is an application for online 2FA. Once set up, you sign in to Facebook with your password and a one-time password (OTP), sent to your mobile device.
Nexus Personal Mobile offers extra security compared to other mobile apps for online two-factor authentication, since you also authenticate your self in Personal Mobile with a PIN code or your fingerprint before you receive the OTP.
A downloaded Personal Mobile application. See here for instructions.