How do I read epub files on iPhone?

Epub is a free and open e-book standard. It's not just one format, but a collection of different formats. The most popular epub format today is EPUB 3. But you can't read epubs on your iPhone or iPad without an app.

The good news is that there are several apps available in the App Store that let you read ebooks in Epub format on your Apple device. Here are some of the best:

GoodReader — A popular choice among Mac users, this app allows you to read any type of document including PDFs, Word documents and more. With GoodReader installed on your iPhone or iPad, simply open up a file from the app and it becomes available for reading on your device. You can also import files from Dropbox or other cloud storage providers directly into GoodReader for reading on the go.