Kindle was easy. As was Barnes & Noble and, by extension, Kobo as they both use ePub format and so the only thing I had to change was the front matter (Nook edition vs. Kobo edition and so on.)
Smashwords was a little trickier, ensuring that the Microsoft Word document conformed to their specifications. But I got it done — although I think there are some additional, unasked for, blank pages in the converted books.
The iBookstore version should have been as easy as B&N or Kobo. Again, it's in ePub format. However the book is not available in iTunes as yet.
I now know why. The book's metadata, the information that goes along with the book, is at fault. That, and the title.
And the autor's name in the cover art must match the name in the metadata. Ah, I have included my middle initial on the cover, but left it out when assigning my name in the metadata.
So, adjustments to the cover art, both for the author's name and the book's title and also the title in the metadata. And they'll be different to all the other forms of the book. Well, the Apple edition will be "special."
It's these little things that irritate me with the way Apple goes about its business. And I am a user of a number of Apple products.