How to turn off Facebook two-factor authentication
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 computer or mobile device we don't recognize. You can also get alerts when someone tries logging in from a computer we don't recognize.
To turn off two-factor authentication:
Go to your Security and Login Settings by clicking in the top-right corner of Facebook and clicking Settings > Security and Login.
Scroll down to Use two-factor authentication and click Edit.
You will see that your two-factor authentication status is on, then click Turn Off.