From the main homescreen, open up your main Settings menu.
Under “Accounts,” select “Add account.”
For this example, select “Google.”
If it is an already existing Google account, simply add in your username and password.
By selecting “New”, your device will have you create a new Google account for use on your Android device.
or
you need to hard reset your device, switch off your device and
Press and hold VOlume UP+Home+Power Button and perform Facroty reset option