KDP
KDP, short for Kindle Direct Publishing, is Amazon's self-publishing platform. Authors upload a manuscript and cover, enter the book's metadata, and set a price; Amazon then sells the ebook in the Kindle store and prints paperbacks and hardcovers on demand. There is no upfront cost — Amazon takes its share from each sale.
For ebooks, KDP accepts EPUB as the standard upload format, along with Word documents and its own Kindle Create output; print books are uploaded as PDFs sized to the chosen trim. A well-formed, validated EPUB is the most predictable path through conversion, since KDP transforms every upload into Kindle's internal format.
Royalty options vary by list price and marketplace, and print royalties additionally subtract printing costs, so authors should check KDP's current terms when pricing. Enrollment choices such as KDP Select trade wide distribution for Kindle Unlimited inclusion. The metadata entered at listing time — categories, keywords, description — is a hand-keyed version of what the industry expresses as ONIX, and it drives how the book is found.