Apple iPhone users will probably have a lot of personal data stored on their smartphone, such as emails, contacts and even sign-in details for social networks such as Facebook. However, this can cause a problem when you decided to swap your existing handset for a new one.
Perhaps you're giving your old handset to a friend or family member. Alternatively you may be selling it on eBay or cash for phone services like Mazuma. Either way, it's wise to remove all your personal data before you pass it on. A factory reset is the best way to do this.
It's also worth remembering to remove the phone's SIM card (if you're not taking it with you) before you pass the handset on, as this may have some of your contacts stored on it .
From the Home Screen select Settings and then General
Now choose Reset and from the options available select Erase all content and settings
You'll be warned the process will delete all media and data, and the reset all settings. Press Erase iPhone and the data removal will begin.