Description
How to Reset iPhone To Factory Default
Resetting your iPhone to factory default will reset it to exactly the same way you first received it when taking it out of the box. You should reset your iPhone if you are selling it, trading it in, or giving it to someone else.
Make sure to back up your phone with iCloud or transfer the data to a new phone before resetting it, because resetting it will delete everything.
You need two things to reset an iPhone. The passcode for the phone and the iCloud password.
If you have an Apple Watch, unpair it from your iPhone:
https://youtu.be/vbe3C8BhUww
Before erasing everything, you need to disconnect Find My, and sign out of iCloud.
Then you can go to general, reset, erase all content and settings.
Finally, you should remove your SIM card. The new owner will need a new SIM card from their cell carrier.
This process works the same way for nearly all modern iPhones including iPhone 12, iPhone 12 Pro, and iPhone 12 mini and max.