In order to hard reset a ZTE A39, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
ZTE A39 device will be brought back to the default configuration of a brand new device.
1. Turn the phone on.
2. Enter the emergency dial and type in this code: *983*22387#
3. Lastly select Erase Everything.