Instead of Touch ID, a fingerprint scanner, it uses Face ID, which can recognize your face, even in total darkness or in direct sunlight. It can't be fooled by photos and simple masks, because unlike other solutions, it uses infrared cameras and dot projectors to scan your face, which Apple calls the "TrueDepth camera system". It can also scan through most eyeglasses and sunglasses, and it can still recognize you even if you change your hairstyle or grow a beard. You can use Face ID for unlocking your phone or for Apple Pay.