How do I stop from using a for digit

With your iPhone you can use Face ID most of the time to unlock your device. Under Settings>Face ID & Passcode you can see your Passcode options. Your Passcode locked device has the advantage of assuring encryption.

If you're trying to stop relying on a four-digit PIN, consider switching to a longer, more complex passphrase or using biometric authentication methods like fingerprint or facial recognition, if available. Additionally, you can explore using password managers to generate and store secure passwords for you.