In order to hard reset a ZTE A88, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
ZTE A88 device will be brought back to the default configuration of a brand new device.
1. Turn off the phone by press-holding the Power button.
2. Open the dialer and type in the *983*22387# phone.
3. Select Yes to confirm the Factory Reset.
4. Voila! The hard reset process is complete.