Suggested approach: If you’re applying for a job at any company that has secure user data, biometric authentication is almost certainly involved somewhere. Fortunately, it’s not hard to learn!
For bonus points mention the need for a password backup in case Face ID/Touch ID fails, but if you're generally stuck here a good approach might be just to say "I haven't used it before, but I have used the keychain for secure storage."
Estimated difficulty: Easy
Link copied to your pasteboard.