We recommend you to convert to the two formats simultaneously – (a) ePUB, and (b) Kindle.

• ePUB has emerged as a common standard followed by the industry and Adobe Systems Inc. has a reading software, Adobe Digital Editions and it is used to read ePUB format eBooks on on several supported devices. '.epub' is distributed by various channels, including B&N's PubIt! for Nook <http://pubit.barnesandnoble.com> and Apple iTunes Connect for iPad <https://itunesconnect.apple.com>. 

• MOBI is the format for digital books which is followed by Kindle/ Amazon(.)com. Kindle format can be rendered on a number of supported devices. The '.mobi' or Kindle format is distributed by Kindle Direct Publishing <http://kdp.amazon.com/>.

By converting to the above formats, an author/ self-publisher/ publisher may attain the maximum reach to the eBooks marketplace.