is a format developed by the International Digital Publishing Forum. It is characterized by the XML- and XHTM-based optional use of CSS styling. The main feature of this format is the use of reflowable text (word wrap) which makes it possible to adapt the image to different device displays. The ePub file is a zip-archive with an .epub extension.
is an e-book format created for Amazon’s Kindle8. This format supports the CSS3 pop-up text system and HTML5 as well as built-in fonts; moreover, it possesses powerful document-formatting capabilities. It contains a function of independently activated DRM protection. AZW3 books can be created with KindleGen, a free software program from Amazon.