Open Settings
Tap General
Tap Transfer or Reset iPhone
Tap Erase All Content and Settings
Enter your passcode if prompted
Enter your Apple ID password if prompted
Tap Continue
Confirm by tapping Erase iPhone
Wait for the iPhone to erase and restart
Open Settings
Tap General
Tap Transfer or Reset iPhone
Tap Erase All Content and Settings
Enter your passcode if prompted
Enter your Apple ID password if prompted
Tap Continue
Confirm by tapping Erase iPhone
Wait for the iPhone to erase and restart