You can set your phone to use your fingerprint as a phone lock code or allow iTunes and App Store purchases. To use the fingerprint sensor, you must have the lock code enabled.
- Press Settings.
- Press Touch ID & Access Code.
- Add a fingerprint
- Press Add Fingerprint ... and follow the on-screen instructions.
- Press Continue. If you have not previously selected the screen lock code, enter the desired code twice.
- Select Touch ID settings
- To turn the feature on or off, press the light next to the iPhone lock.
- If you enable this feature, you can also use fingerprint locks on Apple Pay, the iTunes Store, the App Store, and passwords.