To bid on a Professional Services contract, you must register with eContract Philly. To register, you'll need: Your tax ID number.This website serves as the gateway for the public and for vendors interested in applying for contract opportunities. This is going to be how to fill out the agreement of sale for pennsylvania. View the forms library. A Pennsylvania residential purchase agreement establishes a legal arrangement between a buyer and a seller in a real estate transaction. The Standard Agreement for the Sale of Real Estate is the primary contract used in Philadelphia real estate. Learn more in our latest guide. A Pennsylvania real estate contract is an agreement made when a buyer makes an offer to purchase a property from a seller.