A factory reset will erase all data from your device and is irreversible. This is good to do if you are going to trade in or sell your device. It will wipe all of your personal information from the device.
From the Home screen, drag down the Notification Panel.
Drag down the Quick Settings panel.
Tap the Settings icon.
Scroll to Backup & reset.
Tap Backup & reset.
Tap Factory data reset. Before proceeding, make sure you've specified a backup account. Otherwise, the images, videos, and information on your phone will be permanently deleted.