What's nice about donating vehicles is that someone will come to your house, put the car on a truck and take the car away. You turn over your title and take the license plates and they give you a receipt.
It's very easy.
However, the non profit doesn't get much money at all. The towing company has to get paid and the middleman that disposes of the car has to get paid. The non profit will only get what is left, which can be as little as $100. That $100 is what you can deduct from your taxes.
On rare occasions, what Catbert said applies. If the non profit uses your car or gives it to a needy person to use then you can deduct the full value of the car. But this rarely happens because most of the cars that are donated to charity are sold for scrap/parts or shipped overseas due to the age and condition of the car.