There is no dearth of e-book formats and e-readers out there though not all e-readers support all e-book formats. Take for instance the Kindle which supports the majority of e-Book formats but not all. Those that the e-reader does not support can be converted into a format that it is able to read.
The AZW format
The primary format that the Kindle is perhaps most comfortable dealing with is the AZW format. That is the format that applies to all e-books available from the Kindle store. It is almost identical to the Mobi format and the reason behind it is that the AZW has its origins in the Mobi format. The latter again was created by the French company MobiPocket which Amazon had acquired and went on to engineer the same into the primary Kindle format.
That said, the Amazon AZW format is still a bit different from Mobi in that the former has better compression so that the same e-book in AZW format would take up smaller space compared to Mobi. Also, while the Mobi format is DRM-free, the AZW files aren’t.
Other supported formats
Apart from AZW and Mobi, other e-book formats that the Kindle supports include Microsoft Word file, Plain Text, Rich Text Format, HTML page, Unprotected PRC, compressed PostScript file, Adobe PDF (not all PDF files look the same on Kindles), and HTML page. Plus, Kindles are also able to decipher a couple of image file formats as well which include JPEG, PNG, and the BMP format.
Audiobook formats
The Kindles are also able to play audiobooks as well. The formats it supports include the popular MP3 files. Any audiobook that is saved in the MP3 format can be listened to using a Kinde e-reader. Then of course there are the Audible (AA) and Audible Enhanced (AAX) formats that Kindles are compatible with. All audiobooks from the Amazon-owned Audible come in the above file formats.
Formats not supported by Kindle
The open-source EPUB format is the most notable omission here, so much that there is active speculation Amazon might change its mind on this format sometime soon. Other formats not compatible with the Kindle include LIT and LRF, the latter being created by Sony.
Fortunately, there is software available that can be used to covert an unsupported format into one that the Kindle easily recognizes. Prominent among those include the Calibre or the Kindle Create.
With a keen interest in tech, I make it a point to keep myself updated on the latest developments in technology and gadgets. That includes smartphones or tablet devices but stretches to even AI and self-driven automobiles, the latter being my latest fad. Besides writing, I like watching videos, reading, listening to music, or experimenting with different recipes. The motion picture is another aspect that interests me a lot, and I'll likely make a film sometime in the future.