Moodle Plugins directory: Set: Assignment: PDF | Moodle.org
Assignment: PDF 
The PDF Assignment submission and feedback plugins (Moodle 2.3 onward) replace the previous UploadPDF assignment type (Moodle 2.2 and prior). The submission and feedback plugins are intended and best used together.
assignsubmission_pdf
This allows a teacher to annotate and return PDF files that have been submitted by students. Teachers can add and position comments and draw lines, ovals, stamps, rectangles and highlights onto the student's work, from within the browser.
Latest release: 595 sites 91 downloads 33
assignfeedback_pdf
This allows a teacher to annotate and return PDF files that have been submitted by students. Teachers can add and position comments and draw lines, ovals, stamps, rectangles and highlights onto the student's work, from within the browser. For Moodle 2.6 and above, I advise you use the standard functionality instead.
Latest release: 555 sites 86 downloads 18