Kindle Create is the latest program (2017) to provide Kindle format for eBooks. (KFX)
Descriptions are from the web site.
If you've prepared a book in Microsoft Word, Kindle Create (Beta) helps you convert it so it's ready to publish to Kindle devices and apps. Kindle Create (Beta) makes it easier to go through the file conversion process, preventing the kinds of errors that can slow down publishing.
Kindle Create (Beta) helps you
- Preview and edit your book as it will appear in Kindle format--before you publish
- Create and edit your table of contents while styling your book.
- Add professionally-designed themes to make your eBook better-looking and easier to read
 Device support
eBooks created using Kindle Create (Beta) can be read on all Kindle devices and apps. Kindle Create (Beta) will output different versions for older devices: devices that don't support enhanced typesetting or Page Flip, in particular. Enhanced Typesetting and Page Flip are available on all Kindle e-readers from the Kindle paperwhite 2 onwards, Kindle Fire Tablets from Kindle Fire HDX 2013 series or newer, and the Kindle reading apps for iOS (iPhone/iPad), Android and PC/Mac Kindle reading Apps.