If you have an older iPhone or iPad that you want to restore it to its original factory condition, give to someone or donate to charity you should remove all your personal content.
Here is what you do:
- Open “Settings”
- Tap “General”
- Scroll to “Reset”
- Tap it and a list of possible actions will be shown
- Tap “Erase All Content and Settings” to return the device to its original factory condition.
All your personal data and apps will be removed forever including your Apple ID. When it is turned on next it will go through setup as if it were straight out of the box.