View the forms library. This is going to be how to fill out the agreement of sale for pennsylvania.You can submit a request for an agreement online through the Philadelphia Tax Center. Here's how: Log into your Philadelphia Tax Center profile. The commission agreement template takes you step-by-step through the information necessary to complete the agreement accurately. A Pennsylvania residential purchase agreement establishes a legal arrangement between a buyer and a seller in a real estate transaction. Pennsylvania Commission Agreement is a contract between an employer and an employee for work paid on commission.