That's why Facebook lets you set up two-factor authentication (2FA). As reported by TechCrunch, if you set up a phone number to use with Facebook's two-factor authentication system people will be able to search for you by that phone number. Most other spots where you might enter your phone number on Facebook can be blocked from prying eyes. That's not the case with your two-factor phone number. Keep your number privateYou don't have to hand over a phone number to use 2FA with your Facebook account.

Source: Forbes March 04, 2019 16:41 UTC