Epub format or pdf format is required.

First, open the microdisk and find the book you want to read. You can enter the name of the book, find the resources in the corresponding format in the list, or add a pdf or epub suffix to the book name. After downloading the book, it can't be opened on the microdisk. Click to select an opening method, and then select "Copy to iBooks" in the application that appears. Open iBooks again, and you will see the book you just copied in the list.