Sometimes you do not have the bandwidth or expertise to write a complex government proposal, and you need someone else to do the heavy lifting. I will help you gather content on your side that we need to mount a successful bid, and I will write up a draft and final for your review.
You know your company better than anyone. You know what you've done. You know who was involved, and you have all the details.
As such, at the start of the engagement, I'll provide you with an outline and a list of information I have (if anything), as well as what I need from you. One I get what I need, I will write up a draft for your consideration, and you will need to review and edit to make sure you are happy with the content and style, and make sure I have represented your offer appropriately.
I will then incorporate any changes you like, and send it to you and your team for finalization and submission. I leave the full branding and graphics to your team unless provided with workable templates up front. Once provided, submitting the bid is up to you, but I will work with you up to the deadline to help make sure it gets done on time.
Typically this is not exactly the "fire and forget" type solution to bid writing some might prefer. There is still work to be done on the business side to determine what the best offer could be, who the best references are, and who should be on the project team in the bid (and eventual contract). Of course the pricing offer is purely a business decision and rests with you to decide. And in the end, you own the bid text: It's your offer, and your contract and project.