Import books, audiobooks or PDFs in Books on Mac
If you have books or audiobooks that you didn’t get from the Book Store or Audiobook Store, or PDFs that you want to open in Books, you can import them into Books.
In the Books app on your Mac, choose File > Import.
In the Open dialogue, select the books, audiobooks or PDFs you want to import, then click Import.
Note: You can also drag and drop books, PDFs and some audiobooks into your library.
If you have imported books, purchased audiobooks and PDFs on your other devices, you can use iCloud for Books to see them on your Mac.