Wash. Rev. Code § 63.14.030
The retail seller shall deliver to the retail buyer, at the time the buyer signs the contract, a copy of the contract as signed by the buyer, unless the contract is completed by the buyer in situations covered by RCW 63.14.060, and if the contract is accepted at a later date by the seller, the seller shall mail to the buyer at his or her address shown on the retail installment contract a copy of the contract as accepted by the seller or a copy of the memorandum as required in RCW 63.14.060. Until the seller does so, the buyer shall be obligated to pay only the sale price. Any acknowledgment by the buyer of delivery of a copy of the contract shall be in a size equal to at least ten point bold type and, if contained in the contract, shall appear directly above the buyer's signature.
RCW 63.14.030
Application, saving-1981 c 77: See RCW 63.14.903.