Notebooks 10 does not support the optional PDF Reader any more (it was available in Notebooks 8). The main reason for this move is that you can now have free PDF editing apps which are much more capable than our PDF Reader ever was. Still, we want to provide our users with the same functionality we had and offer equivalent alternatives:

  1. Notebooks 10 supports the PDF annotation tools that are part of iOS 13. So you have basic PDF editing tools available simply by tapping a PDF document once. (Notebooks‘ PDF handling capabilities will grow with the next releases).
  2. In Notebooks 10 you can use the “Open in…” menu to open PDF (and other) documents in external apps without duplicating them. So you store and manage your PDFs in Notebooks, but use external apps to open, view and edit them. All changes you make are stored in Notebooks.
    If you need a recommendation for a PDF editing app – and if Apple Books is not capable enough – you could look at the free app PDF Viewer, which is the more grown up version of Notebooks’ former PDF Reader.

Where is the Optional PDF Reader in Notebooks 11?
FAQ