Illinois Class 9 Application-Part I is an application used to register a vehicle in the state of Illinois. It is used to register a vehicle that is nine years old or newer, and it must be filled out in order to register a vehicle. There are three types of Illinois Class 9 Application-Part I form: the Dealer Application, the Private Party Application, and the Transfer Title Application. The Dealer Application is used when registering a vehicle from a dealer, the Private Party Application is used when registering a vehicle from a private seller, and the Transfer Title Application is used when transferring the title from one owner to another. All three applications will require the same information, such as the vehicle's make, model, year, mileage, Vehicle Identification Number (VIN), and the owner's name and contact information.