Found a contract opportunity in PASSPort to pursue? To file invoices for all DEP contracts, vendors must use the DEP Invoice Platform.Vendors will need to create an account upon initially accessing the platform. Bystep guide to understanding the bidding process, along with tips on submitting a successful bid. Bid Proposal checklist. Complete your free Bid Proposal with our Make It Legalâ„¢ checklist. Learn how to write a winning bid proposal for construction projects. This checklist is provided as a convenience to bidders in areas where past experience indicates such instruction can be helpful. The form must be completed fully and contain an original signature of the bidder or its authorized agent. The Bid Proposal Form on page C-4 is a sample.