what file formats are acceptable for kindle
The EPUB files format is accepted by Kindle. However, to ensure proper conversion, it is recommended that you check the conversion with the ePubCheck Tool before uploading the file. Kindle uses the unzipped version of the ePub files and converts them for publishing. Plain Text (.txt)
While Kindle Publishing accepts plain text files for conversion to html, it does not recommend adding images to a text file. This is because images are not converted to the html format. Hence, a .txt format should only be used if your book does not contain any images. Rich Text Format (.rtf)
MOBI files can be created through two different ways. One is through the original MobiPocket Creator and one is through Amazon tools like KindleGen. The former is not accepted anymore and the latter is supported and recommended by Kindle for formatting. ePub (epub)