Sell or give away your iPhone
Before you sell or give away your iPhone, see the Apple Support article What to do before you sell or give away your iPhone, iPad, or iPod touch, and be sure to perform the following tasks:
If you paired an Apple Watch with your iPhone, unpair your Apple Watch. (See the Apple Support article Unpair and erase your Apple Watch.)
Erase all content and settings that contain personal information. If you previously turned on Find My for your iPhone, Activation Lock is removed when you erase iPhone, making it ready for a new owner.