The file format ePub is used for electronic books and publications.
The ePub format can be read on a tablet, a mobile phone, various readers, or a computer. To read, you need a suitable program, such as iBooks (iOS), Google Books (Android), or Adobe Digital Editions (computers).
You can display ePub files natively in Microsoft Edge if you use Windows 10.
Amazon Kindle doesn’t open ePub files.