Also, both buyer(s) and seller(s) are required to sign and hand print their name and date the transfer document. In today's video I'm going to show you how to correctly fill out a Massachusetts title when buying or selling your car privately.Both parties must fill out a bill of sale, documenting the sale price, vehicle details, and signatures. General Bill of Sale – This form would usually be used to provide proof of sale and purchase between two private parties in the sale of personal items.