If you also need to erase your Apple Watch, you can use these steps to unpair your devices.
Tap Settings > General > Reset
Then tap Erase All Content and Settings.
If asked, enter your passcode or Apple ID password
Wait for your device to erase
Depending on your device, it can take a few minutes to completely erase your data.
If you can't erase your device
- If you don't remember your passcode for your iPhone, iPad, or iPod touch, or your device is disabled, learn what to do.
- If you forget your Restrictions passcode, you need to erase your device, then set it up as a new device to remove the Restrictions passcode. Restoring your device using a backup won't remove the Restrictions passcode.
If you still need help, contact Apple Support.