Modern-day iOS devices come equipped with advanced forms of biometric authentication right out of the box, such as Face ID or Touch ID, but you can still resort to an alphanumeric or numeric passcode if you wanted to.
It might seem counterproductive to do such a thing given just how fast and zippy Face ID and Touch ID have become, but a new jailbreak tweak release called Scribble by iOS developer Boo is sure to make you actually want to use your passcode interface over biometric authentication.