Have you written a book? If so, good. Can it please strangers? If yes, great. Will it sell? That depends on who you publish with.
Traditional publishing is difficult to get into. You can get rejected, even if your book is a master piece. If you do get accepted, you have to give up control and wait for your book to be published, which can take months or years.
Self-publishing is easier and quicker. You keep all control and can have a book within hours.
Then there is hybrid publishing. They accept and reject authors, may let them keep their book’s right, and do other things that combine traditional and self-publishing. It’s not exactly the most encouraging, though.
And lastly, there is vanity publishing, which is often called self-publishing by many. They let you keep all the control, but they charge you for publishing (between hundreds to even thousands of dollars) and other services, like press releases, revisions, and more. Despite that, books from those companies usually don’t sell too well, even if they’re well written. I did so much marketing and promotion with them when my books were first published. And even though the books pleased strangers, they only sold an average of 25 copies a year.
I believe it’s because people do not trust vanity publishers. I regret using them. One was fine and I got along with the company. Another, however, constantly forced me to buy services, even if I couldn’t afford them. They wouldn’t let me out of anything. I got mad at them at least a few times.
I’ve learned the (kind of) hard way to not use vanity presses. People apparently judge books by their publishers. Books that may be worthy of becoming bestsellers may hardly sell if published by a vanity press.
Traditionally-published books sell the best. Self-publishing is fine too. In fact, the author is responsible for marketing on their own with either route. Commercial publishers might only market for top authors these days.
If you self-publish, I’d recommend using companies like Amazon’s KDP program. It’s free to publish. People trust books from them more. And books from there tend to sell much better than vanity-published ones. How do you tell if a company is a vanity press? Look for things like publishing packages. So choose your route wisely. I would avoid vanity presses at all costs. It’s better to get traditionally published or self-publish through Amazon KDP or even Ingram Spark.