For example, in the case of the purchase of a used vehicle, provincial legislation often requires a bill of sale to register the vehicle to the new owner. A bill of sale shows that a transaction took place on a specific date, proving that both parties wanted a transfer of ownership. When a vehicle owned by an estate is sold to a third party, a bill of sale (signed by the estate executor or disposer) is required, in addition to the other documents listed here. If you’re considering buying or selling a vehicle, here’s what you need to know about a. For example, an enforceable bill of sale: