If you are resetting the phone to sell it or give it away, you remove your Google account before resetting. If you do not, the phone will lock itself via Google's Factory Reset Protection (FRP) security feature. The new owner will not be able to set up the phone without your Google password.
The phone will now reboot. You will see a black screen with an Android robot animation for 3–5 minutes. Once finished, the Key2 will boot to the initial "Welcome" setup screen, exactly as it did when you first bought it. How to Hard Reset BLACKBERRY Key2
If your phone is still functional, immediately back up your photos, videos, and documents. You can use: If you are resetting the phone to sell