PDF Annotation

Activities ::: mod_pdfannotator
Maintained by Bernd Decker, Friederike Schwager, Tim Schroeder
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.
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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.


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

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Show comments
  • Wed, Sep 16, 2020, 11:17 AM

    How I can disable automatic sending of email notifications every time an annotation is made in the pdf document? Due to restrictions on my web hosting, the server cannot send many emails per hour.

    Thank you.
  • Sat, Oct 17, 2020, 10:20 PM
    Hi, could anyone highlight which part of the code is used to view the document in Moodle. I would like to create this feature for my own plugin and was hoping to take a look on hwo I should go about it.
  • Sun, Nov 15, 2020, 7:54 PM
    Very promising plugin. I too would like notifications to be off bt default. The forum-style settings that are already suggested would be good. But a checkbox per activity or even in the plugin settings would be anough for me.
  • Thu, Feb 11, 2021, 2:58 PM
    I still can not open pdf with this plugin. There is an error while opening the file on the PC browser, I've tried all browsers (chrome, edge, firefox, safari) and it is still not worked.. However it works when I access my moodle through mobile web browsers. Are there anyone here can help me?
  • Thu, Feb 11, 2021, 6:18 PM
    @Randi: Can you please open an issue in the bug tracker for this plugin? It would be helpful if you could add some more information about the error you are getting: error message and/or a screenshot.
  • Thu, Feb 11, 2021, 7:14 PM
    @Randi: Nevermind, I see you already created an issue. Can you provide some more information about the problem? Is there some error in the JavaScript console? Does this only happen with certain PDFs? Have you tried with browser extensions disabled? Have you tried turning hardware acceleration off? Have you tried clearing your browser cache?
    It would be best to continue the discussion in the tracker.
  • Tue, Mar 2, 2021, 3:14 AM
    We recently installed this plug in and it seems to work pretty well. Could you explain what the Unsolved and Solved feature is and how you use it?

  • Wed, Mar 3, 2021, 7:09 PM
    Thank you for this wonderful plugin. I just have a question: each time someone comments on the PDF i get an email. And I cannot find where to stop it (wether in the Plugin Admin Settings nor in the Activity setting in the course). Can you help me? Thanks in advance
  • Mon, Mar 8, 2021, 5:22 PM
    Thank you for this plugin. I have two questions. Is it possible to hide the questions sections and do pdf annotation on full screen. I want to use this tool for tutoring. Second question is: When I click the download PDF tool, the pdf document is downloaded without the annotations. Can I download the PDF with annotations on it. Thanks.
  • Tue, Mar 9, 2021, 9:56 PM
    @Debra Anthony Managers and the author of a question can mark a question as solved/closed. Then other useres can directly see, that the question has been answered sufficiently. On the overview tab it is possible to filter for open/unsolved questions. So you don't have to search through all the old questions to find the unsolved ones.

    @Giulia Covezzi You can disable emails in the notification preferences. In the newest version (which currently is only released on github) the notifications are turned off by default.

    @Çetin Özyurt In the toolbar you can find an button for fullscreen, which hides everything except the PDFAnnotator-Activity. But the question section on the right is still displayed.
    It is not possible to download the PDF with the annotations on it. But you can download the comments separatly.
  • C'est moi :-)
    Thu, Jun 17, 2021, 5:10 PM
    It would be very nice if you could make it (officialy) compatible with Moodle 3.10 and 3.11.
  • Thu, Jul 29, 2021, 8:25 AM
    Hi, is anyone else going through the experience of having the pdf file tripled using this plugin? In our infrastructure this plugin has had this behavior.
    Does anyone have any idea how to resolve this situation?
  • Fri, Aug 13, 2021, 4:46 PM
    @Séverin Terrier Right now we are testing it. After that we will make it compatible

    @Clovis Tristao We never had this issue. Could you please provide some more information about your infrastructure, the steps to reproduce this problem and a screenshot? Also feel free to create an issue in the github repository
  • Fri, Oct 8, 2021, 9:44 PM
    This is a very useful plugin for us. I see it is also possible to enable group mode in the common module settings, but it looks like this is not working as expected. Do yo have plan to support seperate groups working on their own comments? This would be very useful when large classes generate too many comments.
  • Thu, Nov 4, 2021, 3:54 PM
    Hi @John van der Baaren Groups are not supported. We are aware of this issue (https://github.com/rwthmoodle/moodle-mod_pdfannotator/issues/45), but not planning to implement this in the next time. But of course you can provide a pull request
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