Visit our proposal development web page for information on grant writing assistance and further proposal development resources. In this article, we discuss how to write a business proposal letter and we offer sample letters and templates you can use as a guide.The Regents of the University of California ("University") on behalf of the UC Riverside Campus. The following Proposal sections are to be included in the Proposer's response: • Vendor Application Form and Cover Letter: Complete Appendix B, Forms and attach. Cover letter of up to two pages, dividers, and any pages left blank. You can use the cover letter to showcase key wins, client stories, or key features that make your company stand out. 273 Riverside Avenue, Bristol, Connecticut. View a sample "Application for Original Contractor License.