Instructions for Completing the Agreement. Information about the types of contracts available with the City of Philadelphia.You can build onboarding and sales forms that include signature fields, to create signed agreements and contracts without ever touching a physical document. This article gives tips on writing out a design services contract and getting the client to sign it. A signed contract is a legally binding agreement. Click here to learn the requirements to make sure you set your transactions up for success in 2023. What is a Design Agreement? A design agreement is a legal agreement between two parties, typically between a designer or a design firm and another company.