How To Write A Bidding Proposal Letter . You have to be positive and encourage the vendor. Dear ellen, i am writing this letter with reference to the bidding submitted on 23rd november 2020. Proposal Letters Free Word Templates from www.wordstemplates.org To end your proposal letter, tell the reader what he or she could do next. Write a winning proposal in minutes with jotform’s proposal pdf templates. This type of letter if not crafted very well would serve to disappoint which is not often encouraged.