Find "Touch ID & Passcode"
Press Settings.
Press Touch ID & Passcode.
Select option
Select one of the following options:
Turn on use of phone lock code, go to 2a.
Turn off use of phone lock code, go to 2b.
Turn on use of phone lock code, go to 2a.
Turn off use of phone lock code, go to 2b.
2a - Turn on use of phone lock code
Press Turn Passcode On.
If you've already added a fingerprint:
Press Keep or Delete.
Press Keep or Delete.
Key in a phone lock code of your own choice.
Key in the same phone lock code again.
Press Require Passcode.
Key in the same phone lock code again.
Press Require Passcode.
Press Immediately or the required period.
Press Back.
2b - Turn off use of phone lock code
Press Turn Passcode Off.
Key in your phone lock code.
Key in your phone lock code.
Return to the home screen
Press the Home key to return to the home screen.