They come with a bill of sale, which is generally accepted as proof of ownership. A bill of sale may be required by law for tax purposes when the vehicle is licensed, even if it was purchased in a private transaction between two individuals. You should check with the Ministry or Department of Transport to find out the precise requirements in your jurisdiction. Vehicles with an engine capacity below 50cc - usually mopeds - may require a license plate to operate on public roads. The driver may also need a driver's license to operate the vehicle, although it is usually a limited license. Where I live, a moped must have a license plate and the driver must hold a Class M (motorcycle) or a restricted Class M license, which is valid only on mopeds and limited-speed motorcycles (LSM). However, a driver's license and vehicle registration do not identify the vehicle's owner. They only say that the driver is permitted to operate the vehicle and in whose name the vehicle is registered. The vehicle does not have to registered to its owner. A valid bill of sale is accepted as proof of ownership. It must state who the vehicle was purchased by, who the seller was, and when it was sold. I was once asked for proof of ownership of a motorcycle by the police and had to provide them with a copy of the vehicle's bill of sale. I was not required to provide it on the spot, but had to bring it to the station within a day or two.