Be extremely careful. Search YouTube for "ZTE FRP unlock tool free download," and you will find videos with links to .exe files that ask for admin permissions.

A: Permanently. Once the FRP token is deleted from the /persist or /frp partition, the phone behaves as if it has never had a Google account on it. You can log in with a new account freely.

: Run the unlock tool, select your specific ZTE model, and connect the device via USB.