Use Face ID
You can set your mobile phone to use face recognition as phone lock code or to authorise iTunes or App Store purchases.
Find "Face ID & Passcode"
Tap Face ID & Passcode.
Add Face ID
Tap Set Up Face ID.
Tap Get Started and follow the instructions on the screen to set up Face ID.
Tap Done. If you haven't previously selected a phone lock code, key in a code of your own choice twice.
Select Face ID settings
Tap the indicator next to "iPhone Unlock" to turn the function on or off.
If you turn on the function, you can use your Face ID to turn off the phone lock code.
Tap the indicator next to "iTunes & App Store" to turn the function on or off.
If you turn on the function, you can use your Face ID to authorise iTunes and App Store purchases.
Return to the home screen
Slide your finger upwards starting from the bottom of the screen to return to the home screen.