In addition, for bigger organisations, unoconv may become unstable, so we normally recommend setting up a G Suite, OneDrive or other document converter, but in essence, this is a standard feature in Moodle, using the Annotate PDF assignment feedback plugin. That should be enabled in order for all of this to work.
Teaching with Moodle
Grading without Downloading the documents
This discussion has been locked so you can no longer reply to it.