My Apple Books does not have Bookstore or Audiobooks. Why?

My Apple Books app has only three icons on the lower icon bar - Reading Now, Library, and Search. I do not have the Bookstore or Audiobooks, so I can not add anything to myy library. I have deleted and redownloaded the app, but it came back with the abovementioned limitations. I would like to rectify this situation but have no idea how to do it.