Great question, Houstin51!
You can still use the regular screen lock options that typically come on Android mobile devices if you don't want to use the Iris Scanner or Fingerprint sensor for your phone.
Here are the other lock screen options available in your Settings:
Swipe: Swipe the screen to unlock it.
Pattern: Create a pattern that you draw on the screen to unlock your device.
PIN: Select a PIN to use for unlocking the screen.
Password: Create a password for unlocking the screen.
Face: Use facial recognition to unlock your device.
Thanks for being a customer! ^Mel