Do I need to approach a book marketing company to promote my book?

In addition to running several businesses, an engineer is well-known for his work, leadership, and capacity to motivate others to improve student life. He has written three chapters, but he does not have enough time to finish the book. Because they can finish your book quickly and make your story interesting and engaging for readers, he considered hiring a book marketing company. They can also help you with the promotion and formatting of your book. Who can help?