I've checked this phone and indeed it has Android operating system, but there is no technical documentation regarding the factory reset procedure. Therefore, you should proceed with the standard way of factory resetting Android phones. There are two ways to do this:
Using the Reset option in the Settings menu. Go to Settings > Backup and Recovery > Factory Reset.
Turn off the phone, then press Power + Volume Up + Home button until the Recovery menu appears. Use the volume buttons to navigate through options and Power to confirm. Choose Wipe Data/Factory Reset and confirm with the Power button. It might take a while but the phone will be restored to factory condition.
