To format a book means to arrange its content in a visually appealing and readable way. This involves setting the font, spacing, margins, and other elements that make the book look professional and organized. 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)