on Just Publishing Advice:
If you are a Mac user, it’s quick and easy to format an ebook in Apple Pages.
Yes, there are lots of program choices when it comes to ebook formatting. You can use Microsoft Word, Calibre or Kindle Create.
But Apple Pages has a few advantages that makes it simple to get your ebook ready for publishing. The first advantage is that it is a free download from the App Store.
The others are that you can import most common files such as docx, easily add images, and when you are ready, you can export in epub format.