How to prepare your old iPhone for sale or give away — Apple World Today

Tap the info button next to the watch that you want to unpair. Tap Unpair Apple Watch.

Sign out of iCloud and the iTunes & App Store. If you’re using iOS 10.3 or later, tap Settings > [your name]. Scroll down and tap Sign Out. Enter your Apple ID password and tap Turn Off.

If you’re using iOS 10.2 or earlier, tap Settings > iCloud > Sign Out. Tap Sign Out again, then tap Delete from My [device] and enter your Apple ID password. Then go to Settings > iTunes & App Store > Apple ID > Sign Out.

Go back to Settings and tap General > Reset > Erase All Content and Settings. If you turned on Find My [device], you might need to enter your Apple ID and password. 

If asked for your device passcode or Restrictions passcode, enter it. Then tap Erase [device].

If you’re switching to a non-Apple phone, deregister iMessage. If you transferred your SIM card from your iPhone to a non-Apple phone, put it back in your iPhone.

Make sure that you’re connected to your cellular data network.

Tap Settings > Messages and turn off iMessage.