There are different types of digital partners who can help you get your books on Apple Books:
Aggregators help format, deliver, and manage books. If you don’t know how to create digital books or if you need production help, consider working with an aggregator. They may also offer book status updates and sales reports, as well as marketing and operational help. If you sell any books, we will pay the aggregator directly, and then aggregator pays you.
Conversion houses specialize in converting books into files for Apple Books. If you prefer to manage your own books and account, but don’t know how to create books in the EPUB format, you may want to work with a conversion house. If you sell any books, we will pay you directly.
Delivery houses can deliver books that have already been formatted for Apple Books on your behalf. They don’t provide formatting services.