Open, modify, and fill in vendor thursday at clark quickly on FormsPal! A reliable online service to obtain and forms promptly.1. Gather necessary information and documentation. The vendor must download the Vendor Agreement from the attachment tab, fill in the requested information and upload the completed agreement. Clark requires suppliers to receive Purchase Orders and submit Invoices electronically either via Coupa Supplier Portal (CSP) and cXML. Transmission. Membership in the Keystone Purchasing Network (KPN) is as simple as completing this application form, at no cost to the Agency. Clark Rents offers various heavy and construction equipment rentals in NY State. Find an equipment rental near you today. A sample contract can be viewed online (click here). The deliverables set forth in the Contract are complete or the City terminates the Contract.