The key documents in a seller financing transaction include: (1) Purchase Agreement; (2) Promissory Note; and (3) Deed of Trust. Seller financing or owner financing enables the property seller to act as a mortgage lender to the buyer.Seller financing can streamline the home purchase. These are the steps typically involved with closing a seller-financed real estate transaction with a Promissory Note and Deed of Trust. Not a lawyer, but it seems like it would be better as separate docs just so things don't get mixed up. When all of the conditions of the Purchase Agreement have been met, you will sign your loan documents. Seller Financing (Purchase Money Note). A prudent buyer's agent preparing a purchase agreement calling for seller financing will have their buyer fill out a credit application prior to.