In most places you're allowed to drive the car or other vehicle without a license plate from the place you bought it and to your home or wherever you plan to keep it and that's it.
You cannot continue to drive the vehicle without a license plate even if you just bought it.
You have to get it registered and have a license plate on the vehicle to continue to drive it.
You also need to have the title in your name and proof of insurance with you for the vehicle.
Also never drive the vehicle with the sellers license plate on the vehicle, be sure to remove the sellers license plate before you drive the vehicle home.