File Handling: for ebooks you need the e-Pub or Mobi file or simply a PDF. You can always adapt the e-Pub file to the appropriate version using free software or upload it to your digital library such as Amazon, Google, etc.
e-Book converter for Linux/Mac/Windows/Android/Flathub
(normally free software)
e-Book converter App for WINDOWS Epubor Ultimate for MAC/WINDOWS CBconvert for WINDOWS/ LINUX/ FLATHUB/ MAC Calibre for for WINDOWS/ LINUX/ FLATHUB/ MAC Any eBook Converter for WINDOWS