With the release of Apple’s newest iPhones, the basics of how to utilize this common product have been altered. The large applications and the Home button are no longer on the phone, which implies Touch ID is no longer available for users. Passwords are also another object that confuses people as they use their phones. There are just too many to remember, so with the easy access of Face ID, it is an easier and secure way to log into apps.
Open the Settings application on your iPhone.
Click the button that says the Face ID & Passwords there is a section labeled Other Apps.
Tap on this to see the apps that you have either denied or granted access to with Face ID. By clicking on the bar to select the Green Color, you have enabled the Face ID.