Oprah's Book Club was just a discussion group about a book that was chosen by one of her production staff from among all the books sent in by publishers for consideration. Anyone could chime in. The book club ceased to exist in 2011. Oprah and her OWN network do not accept manuscripts (or other material such as videos) for consideration.
The best way to get your book published is to send it to small publishers. Large publishing houses will only accept manuscripts from a literary agent.
You can read more here:
You can also publish the book yourself. You can read more about that here: https://janefriedman.com/self-publish-your-book/