In order to hard reset a BlackBerry Z3, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
BlackBerry Z3 device will be brought back to the default configuration of a brand new device.
1. First, power up the phone by pressing the Power button.
2. Choose Settings, then Security and Privacy and then Security Wipe.
3. When prompted to, type the word "BlackBerry" into the phone.
4. Woohoo, the phone resets and restarts and the hard reset is complete. Pat yourself on the back and open up a bottle of beer.
5. Select the Delete Data option and watch as your phone resets and restarts. Voila.