Apple's mobile phone uses ibook, which can be directly imported through the PP helper book function.

The specific operation is as follows:

Connect the device to the PP assistant, click on the book bar, and the PP assistant will automatically detect whether the device is equipped with iBooks. If not, please follow the prompts to install.

After installing iBooks, click Library Bar-Import-Import File, and then import files in epub and pdf formats.

After importing, directly open iBooks on the device for reading (if you can't view the book file when opening, you can choose the PDF format at the top of iBooks).