I am running Moodle 3.3 on a VPS with Ubuntu 16.0.4, PHP 7.2, MariaDB 10.1 managed in an app sandbox through RunCloud. I'm trying to test the assignment annotation feature, but it is simply not showing up anywhere. I followed the Moodle documentation and allowed Comments inline, file feedback, and accept PDF submissions. When opening the grading screen, there is no PDF annotation editor, no option to launch anything of the sort. Clicking on the submitted file merely downloads the PDF. There is no error suggesting there is anything wrong, it is simply missing.
I haven't made any substantial changes to default Moodle, but I also don't have Ghostscript. Is installing ghostscript necessary for the editor to even show up? What am I missing? Is the function somewhere else or do I need to do something to make it available?
Thanks to anyone that can shed light on this.