PDF Online Reader is a free online tool that allows you to view and annotate PDF files directly in your web browser. The online PDF viewer can also highlight text and add hyperlinks.
Demonstrated by @woodrowbound at our TeachEat. Super simple tool and allows students to annotate and comment on an online PDF'ed document and then download.
Good set of editing tools and easy to use.
Via gideonwilliams, Juergen Wagner