- Ensure that you have made backups of your iPhone files to either cloud services like iCloud or locally to your computer via iTunes. This reset procedure will make your iPhone files unrecoverable.
- Before a reset can be performed, you will need to disable Find My iPhone on this device. This measure is necessary so that only the owner is able to erase the phone. Go to Settings > iCloud > Find My iPhone. Tap the Find My iPhone toggle to disable this service. You will be asked for the Apple ID password associated with this device. An Internet connection is required to disable Find My iPhone, either Wi-Fi or cellular data.
- Now that Find My iPhone is disabled, you are ready to perform the factory reset.
- Go to Settings > General > Reset, and tap “Erase All Content and Settings”.
- Enter your device passcode when asked and follow the prompts on the screen.
- The iPhone will shut down and reset to a factory state. When the device reboots, you will see the Hello/Welcome screen as if it is a brand new iPhone.
The entire process takes only a few minutes to complete because modern iPhones have encrypted storage. This means there is no need rewrite the entire flash storage chip, only the encryption key, and device configuration is reset.