An EPUB is an ebook file. It usually reads better than a PDF because the text can adjust to your screen.

Best options for epub readers

Apple Books
Best for iPhone, iPad, and Mac. On a Mac, Apple says you can import books by choosing File > Import, or by dragging the book into your Books library.

Google Play Books
Good for Android, Chromebook, or browser-based reading. Google says readers can upload PDF and EPUB files to their Play Books library from a computer.

Adobe Digital Editions
Good for Windows or Mac. Adobe describes it as a free reader for EPUB and PDF books (Adobe Digital Editions).

Calibre
Best for readers who already like managing ebook files. Calibre supports Windows, macOS, and Linux (calibre-ebook.com).

Not sure what to choose? Download the PDF instead. It opens on almost any device.