PDF Annotation

Activities ::: mod_pdfannotator
Maintained by Bernd Decker, Friederike Schwager, Tim Schroeder, Anisa Dewi
The PDF annotator allows students to insert questions, comments and remarks on learning materials in PDF format directly into the document. Since all students, lecturers and tutors can read and answer the questions and comments asked, it is made easier to clarify open questions on lecture slides, scripts and other PDF learning materials quickly and in a concrete context.
Latest release:
2650 sites
73 fans
Current versions available: 3

What is the PDF-Annotator?

The PDF annotator allows students to insert questions, comments and remarks on learning materials in PDF format directly into the document. Since all students, lecturers and tutors can read and answer the questions and comments asked, it is made easier to clarify open questions on lecture slides, scripts and other PDF learning materials quickly and in a concrete context.

The PDF annotator is integrated into Moodle. You can recognize the PDF annotator by this  icon: The following screenshot (Fig. 1) gives you an impression of what the annotator looks like. On the left side of the PDF are the annotations, for which there are different tools. In the column to the right of the PDF you can write a comment on the annotation or respond to existing questions and comments from students. Comments may contain references to an important passage, an error, or a question to be answered by other students.

All annotations and comments are public and therefore visible to others. However, comments, as well as replies to existing comments, can also be posted anonymously.

Add PDF annotator to the course

To use the PDF annotator and add it to your course, click Turn On Edit at the top right of the Moodle page. Then click on ADD AN ACTIVITY OR RESOURCE in the desired area in which the PDF annotator is to be displayed and select PDF ANNOTATION from the list. Then click on ADD and you will be forwarded to the overview page where you can make further settings, such as the name and a description for the document. In the next step, please upload the intended PDF document. You can do this either using drag & drop or the file manager.  You also have the option of availability, prerequisites and activity completion.

to be determined. If you do not need these settings, simply leave them untouched, after uploading the file and clicking on SAVE AND TO COURSE your PDF document will be displayed directly in the desired area.

NOTE:  also drag and drop a PDF into a Section (editing on), you will be asked "Create file for PDF Annotation".

Toolbar for annotations

Use the toolbar to select the different annotation tools. With these you mark a place or area in the PDF, for which you can then write a comment or a question.


Fig. 2 The toolbar

  • Cursor: With the cursor you can select, comment or move existing annotations.
  • Pin: Use the pin to mark individual points in the PDF to ask questions or leave a comment.
  • Bounding box: Use the frame to select individual text or image areas and create comments for them.
  • Highlighter: Use the highlighter to highlight parts of the text and make comments on it.
  • Cross-Out: With this tool you can cross out and comment on incorrect parts of a text. 
  • Text: With this tool you can insert additional text into the PDF and comment on this insertion. In addition, you can select the font size and color before writing.
  • Pen: With the pen you can paint freehand in the PDF and create comments. You can also select the pen width and pen color before drawing.
  • Zoom: With the zoom you can display the PDF larger or smaller.
  • Hide annotations: To view the original document, you can hide all annotations. Note: With another click on the open eye, all annotations can be shown again.
  • Fullscreen: In full-screen mode, the entire PDF annotator is displayed across the width of the screen.
  • Page count: The page number shows you where you are in the PDF document.
  • print pdfDownload document: Download the PDF document
  • Download comments: Download all Discussions as PDF

Create annotations and comments

If you select an existing annotation or create a new one, a comment field opens on the right. Here you can enter your questions or comments.

If you want to post anonymously, activate the checkbox Post anonymusly. With a click on CREATE ANNOTATION or ANSWER you can send your text. However, it is recommended that you do not post anonymusly.

Overview all annotations

The Teacher Overview provides an overview of various elements of the PDF annotator. You will receive a presentation of the reported comments, new questions will be made directly accessible here and can be accessed via the link on the right-hand side, you can continue to view your contributions to comments of the students in this presentation and additionally administer entries.


Since v1.5.1, PDFAnnotator are supporting the Atto Editor. Another editor will not work for this plugin. Please make sure, that you are using atto editor as your standard editor.


Screenshot #0
Screenshot #1
Screenshot #2
Screenshot #3
Screenshot #4


Bernd Decker (Lead maintainer)
Friederike Schwager: Developer
Tim Schroeder: Developer
Anisa Dewi: Developer
Please login to view contributors details and/or to contact them

Comments RSS

Show comments
  • Thu, Dec 8, 2022, 1:54 AM
    @Anisa - I installed version 1.5.3 and still receive the same problem. I upload a pdf file and i keep getting: An error occurred while opening the PDF file.
  • Fri, Dec 9, 2022, 8:15 PM
    Hi Anisa, iI have two possible bugs to report.
    1) Settings for Textbox and Drawing do not seem to work. Whether selected or unselected, their icons always show on the annotation toolbox.
    2) The language string of the helpnote for "Enable drawing for participants? " is the same as that for "Save and print pdf document"
  • Mon, Dec 12, 2022, 9:36 PM
    @Eldrigde which browser did you use and which version? For the new release because of update of mozilla/pdfjs, we need the minimum supported browser versions (see: https://github.com/mozilla/pdf.js/pull/13379). I would recommend you to update your browser version first, or you can open an issue in our github (https://github.com/rwthmoodle/moodle-mod_pdfannotator) and provide e.g. screen shots of the browser console and the browser version.

    @synnac thank you for reporting. We well check it.
  • Tue, Dec 13, 2022, 5:13 AM
    @Anisa Dewi
    Thank you for the response, the language string errors have now been fixed.
    Keep up the great work.
  • Tue, Dec 13, 2022, 11:30 PM
    Is there a date when the update for Moodle 3.11 (.11) will be released that fixes the language issues?
    I had already updated to 1.5 and would have to adjust a few language strings.
    Since the version is currently offline and the problem has already been fixed for later versions, the problem should probably already be worked on.
    Thanks for an info!
  • Wed, Dec 14, 2022, 5:03 PM
    the latest release is still compatible with 3.11.
  • Wed, Dec 14, 2022, 6:23 PM
    Thank you very much!
    I was surprised because the version for 3.11 is currently not available.
    The version for Moodle 4 was not offered to me in the automatic update. But after the manual installation it works!
  • Mon, Jan 2, 2023, 7:37 PM
    Hello, I am doing my final degree project based on pdf annotations in moodle, and your plugin is very interesting for it. The thing is that I am required to adapt it to the needs for my project, so I will like to know how could I access the code and make some modifications on it to try it on my local host and achieved my objective for the project. Thank you in advance for your help
  • Thu, Jan 5, 2023, 10:09 PM
    Hello guys,
    @samai thank you for using our plugin for your final degree. You can find our source code here: https://github.com/rwthmoodle/moodle-mod_pdfannotator and make a clone to your local repo.

    @synnac we have checked the problem you mentioned about the settings for textbox and drawing. There was no bugs on it. The settings are for students. As long as you are an admin or manager you can see both annotations. But, you are right with the setting descriptions. They do not correctly describe the settings. We have added this improvement to our backlog. Thanks for reporting.
  • Thu, Apr 27, 2023, 7:11 PM
    Hello, as I told you before, I am doing my final degree project based on your moodle plugin pdf annotator. I need to make some changes, could you help me with that? For example, I wanted to add the posibility to add comments to the drawing tool. Could someone tell me which file I need to change to achieve that? I am not very acquaintance with php. Thank you very much in advance for your help
  • Tue, May 2, 2023, 5:13 PM
    Hello, I'm going to upgrade to Moodle version 4.1.3 but I see that this plugin is available until Moodle version 4.0.
    Do you know when it will be available for Moodle version 4.1.3?
  • Tue, May 23, 2023, 4:20 PM
    How to you turn off email notifications for this plugin?
  • Tue, May 23, 2023, 10:12 PM
    @samai each commentable annotation type, such as pin, highlighting etc.. call a callback function in index.js. It will call a function in lib.php names mod_pdfannotator_fragment_xxx. If you wanna add a question or a comment, it will triggered an event listener and call action.php. The action.php contains all events we need for pdfannotator.
    @cristina we have published a new release today. Please have a look smile
    @aldwin every user can turn it off in notification settings. Go to user preferences -> notifications preferences -> look for pdfannotator. Or what notifications do you mean?
  • Fri, Jun 16, 2023, 3:08 PM
    Hello, our lecturers really love the pdf annotator - its just great for arts education, thank you so much for this plugin!
    However, since we updated to Moodle 4.1 it's no longer possible to activate the pin and add comments to the pdf (while drawing lines or adding text on the pdf is working).
    Do you have any suggestions what might cause this issue? (Moodle 4.1.2, PDF Annotator v1.5 release 4 2023052300)
    Thank you so much, best regards, Katja
  • Fri, Jun 16, 2023, 5:37 PM
    Thank you for using our plugin smile
    I cannot recreate the problem. Can you tell me your browser and its version, your operating system, and what in your browser console is? Are there any errors or something?

    best regards
1 2 3 4 5
Please login to post comments