Do any of the following:
Select Home to see what books and audiobooks you’re reading across your Apple devices.
Select “Collections, bookmarks and highlights” to see your collections, bookmarks, highlights and recent book info across your Apple devices.
On your Apple Watch: By default, you can sync up to two audiobooks from your Home or Want to Read collection to your Apple Watch. You can also sync audiobooks to your Apple Watch manually. See Import books, audiobooks or PDFs in Books on Mac