Here’s some step to follow before you sell away your iPhone.
- If you have an Apple Watch paired to your iPhone, you will need to unpair it using the Watch app.
- Next up, you need to backup your data. You can do this by connecting the iDevice to a PC or Mac with iTunes installed, or to iCloud (iOS 8 users can check the status of this at Settings > iCloud > Backup, while iOS 7 or earlier users need to go to Settings > iCloud > Storage & Backup).
- Next, you need to sign out of iCloud. Tap Settings > iCloud and then scroll down and tap Sign Out. In iOS 7 or earlier, tap Delete Account.
- You will be asked to confirm the action. Tap Sign Out again, then tap Delete from My iPhone (you will be asked to enter your password).
- Now to delete your data. Go to Settings > General > Reset > Erase All Content and Settings. If you have Find My iPhone enabled then you may need to enter your Apple ID and password. If you are asked for your passcode or restrictions passcode, enter it and then tap Erase iPhone.
There is no recovery possible – apart from reloading from a backup – after this step. - Job done. When the device is next powered up, the Setup Assistant will guide the user through the setup process.