I love the idea of registering it as a printer. Right now I do something similar (but more cumbersome) with my iPad Pro: I print to PDF, save the PDF in iCloud

I love the idea of registering it as a printer. Right now I do something similar (but more cumbersome) with my iPad Pro: I print to PDF, save the PDF in iCloud Drive, and then open it in Preview on the iPad, which lets me annotate it with the Pencil. What I really wish I could find is some way to do the same for e-books. Amazon, if you're listening, it'd be a game changer if you could support this in the Kindle app.