This template gives you everything you need for a professional, customizable and legally binding Bill Of Sale Motor Vehicle Illinois.
Not required by law, but Illinois often wants proof of the transaction for title transfers and tax purposes. Smart to have one even though the state doesn't provide an official form.
Full names, vehicle description with VIN, purchase price, sale date, signatures from both people. You'll also need Form VSD 333 for odometer disclosure when you do the title transfer.
No notary needed for the Bill of Sale itself. But the seller has to file Form VSD-703 with the Secretary of State right after the sale. Don't forget that part.