How to setup Touch ID for the Lock screen February 17, 2015 09:42
1. Launch the Settings app from your Home screen.
2. Scroll down and tap on Touch ID & Passcode.
3, Enter your passcode if prompted.
4. Under the Use Touch ID For section, turn On the option for iPhone Unlock.
If you’ve never used Touch ID before, iOS will take you through the fingerprint setup process. If you have, your existing fingerprints will once again be enabled.