The phrase "format books" means to arrange or prepare books in a specific way so that they look neat and organized, usually involving the layout, design, and appearance of the text, images, and other elements within the book. Full definition
I offer developmental editing, copy editing and line editing / proofreading, as well as assistance with formatting books for publication in both ebook and paperback formats. (badnovelist.com)
This post deals with the technical aspects of formatting a book interior. (ask.aliannedonnelly.com)
I wish someone would offer the service to format books on all the sales channels at a reasonable price. (kaitnolan.com)