When I first published Wilde Accusation with kdp, which is Amazon's self-publishing platform I had intended to also publish on Barnes and Noble, Google Books, and Apple Books. I discovered that I can't publish to Apple without an Apple device. My computer is a PC and my tablet and phone are android. So, Apple Books was not an option.
Then I discovered Draft2Digital. With Draft2Digital I would be able to publish to Apple Books, Barnes and Noble, Kobo, and Smashwords. If I used D2D they would...