Is it illegal to have no license plate on the front of your car and put it in your windshield?
Pennsylvania only requires one on the back of the car.
I think by law you need a license plate in the front and in the rear of the vehicle. Some states may be different on this. I have seen custom picture plates in the front instead of the regular plate. You can ut it in the windshield area temporary.
Depends on you state. Call you local DMV.
Depends on the state - in VA you have to have one on both the front & back.