1. Find "Touch ID & Passcode"
Press Touch ID & Passcode.
2. Add fingerprint
Press Add a Fingerprint... and follow the instructions on the display to add your fingerprint.
Press Continue. If you haven't previously selected a phone lock code, key in a code of your own choice twice.
3. Select Touch ID settings
Press the indicator next to "iPhone Unlock" to activate or deactivate the function.
Press the indicator next to "iTunes & App Store" to activate or deactivate the function.
4. Deactivate use of phone lock code
Press Turn Passcode Off and key in your phone lock code.
5. Return to the Home screen
Press the Home key to end the session and return to the Home screen.