We'll help you craft the best vendor contract agreement for your specific needs, and help you manage that relationship as long as you need it. Below is a list of forms and information that may be required to complete a Request for Proposal Response.This tool allows the general public and other interested parties to browse information associated with CHA contracts and vendors online. These forms are also available in the DotLoop and DocuSign form libraries. There are two ways to become a vendor for Chicago Public Schools: 1. Create, commit to, and manage your agreements all in one platform with Docusign IAM. Electronically sign for free. All vendors submitting bids and offers on Illinois public contracts must: 1. Be a legal entity authorized to transact business or conduct affairs in Illinois.