Depending on your device speed, it can take a few minutes or less to completely erase all your personal data, information and settings
You need to enter your passcode and Apple ID password before you erase all content and settings.
, Heres the walkthrough
On your iPhone, iPad, or iPod touch, go to
1. Settings >
2. General >
3. Reset >
4. Then tap Erase All Content and Settings.
5. Put your passcode