A factory reset will restore your phone to the settings that were configured in the factory. All of your personal data from the internal device storage - including account information, system and application settings and any downloaded applications - will be erased.
Important: Back up your personal data before performing a factory reset.
Backing up personal settings
1. On the Settings screen, tap Backup & Reset.
2. Tap Back up my data, and slide the slider to On.
3. Tap Backup Account.
4. A popup window will appear to set back up account, tap + Add account.
5. Sign in to your Google Account,
Factory resetting the device
1. On the Settings screen, tap Backup & Reset > Factory data reset.
2. Tap RESET PHONE and then tap ERASE EVERYTHING. The device will reset to the original factory settings, and then restart.