Face ID is a new biometric authentication system Apple. It replaces the Touch ID system that is built into the Home button. iPhone X doesn't have this button, so there is Face ID. To unlock your phone, you need to bring it to your face and look at it.
This can save you a couple of seconds of time every time you need to use your iPhone X (which adds up to a lot of time), but you won't be as secure as before. Apple assures that the probability that someone else will be able to unlock your iPhone X is one in a million. The only exceptions will be those who have an evil twin.
Luckily, like Touch ID, Face ID on iPhone X can be temporarily disabled if the need arises. When you turn off the system, you will need to enter the password to unlock the phone,
How to temporarily disable Face ID
To temporarily disable Face ID, simultaneously hold down the Volume Up + Volume Down + Side buttons. The buttons must be pressed at the same time, and this can be done by simply holding the top of the phone. This is advice from Craig Federighi himself.
This method is especially useful when you are in a situation in which you can be forced to unblock iPhone using Face ID. You can quickly squeeze the top of your phone by pressing all the buttons at once. It can even be done in your pocket or bag.
Disable Face ID with an Emergency Call
The Emergency method – SOS should work on iPhone X. If you have this feature enabled, quickly press the Side button 5 times and a screen with an emergency call and medical card will appear. Click Cancel and Face ID will be disabled after that.