How can book writer benefit me with my book?

I was tasked with writing a book about my company, where I have worked since its inception, by one of its board directors. in addition to the work and responsibilities of each department head, which employees must complete within the allotted time. Because I'm terrible at marketing and planning, a coworker suggested that I hire book marketing services because they can do it for me and provide creative plans in an expert manner. Can somebody assist me?