A master reset will result in the loss of all data stored on the device including 3rd party applications.
This type of reset should only be used as a last resort after all other troubleshooting steps have been exhausted. It is highly recommended that you complete a backup of the device information before proceeding with the steps in this tutorial.
From the home screen, tap Settings.
Scroll to and tap Reset.
Tap Erase All Content and Settings.
Tap Erase iPhone to confirm.
Tap Erase iPhone.
Note: If prompted, enter the Apple ID password, then tap Erase.
The phone will now be reset to factory settings.