All invoices are to be delivered to the address indicated in the purchase order. An MSA, or Master Service Agreement, is a contract between a company and a vendor that outlines the terms and conditions for services the vendor will provide.THIS MASTER EQUIPMENT LEASE-PURCHASE AGREEMENT (this "Master Agreement") is made as of. Must get an attorney to form the master lease agreement. An MSA is a contract between two or more parties that establishes what terms and conditions will govern all current and future activities and responsibilities.