Hard Reset ZTE Kis 3 Max

First method:

1. Firstly hold down the Power key to switch off the mobile phone.
2. Then press and hold together Power + Volume Up button for a couple of seconds.
3. You can release held keys when you see an Andoid image.
4. Afterwards press the Power button to enter Recovery Mode.
5. Choose "wipe data/factory reset" by using Volume Down to navigate and Volume Up buttonto confirm.
6. Select "Yes--delete all user data". Use Volume Down button to scroll and Volume Up to select.
7. To restart the phone, select "reboot system now".
8. Success! The hard reset is done!

Second method:

1. Turn on the phone by using the Power button. 
2. Then from Main Menu go to Settings and then to Backup & reset.
3. Choose the Factory Data Reset.
4. Tap Reset Phone. 
5. Select Erase Everything if you are sure you want to clear all your data. 
6. Well done!

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.