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Home / Blog / How to Add Comments to PDF in 3 Free Ways [Complete Guide]

How to Add Comments to PDF in 3 Free Ways [Complete Guide]

By Charlotte | Follow twitter | Updated on December 13, 2022
When you review a PDF document and need to mark up the content to be modified, adding comments such as sticky notes and text to it might be essential. However, because PDF files are designed for easy sharing but not editing, it can be a headache to add comments to PDF. That’s why we write this article to help.

This post will introduce the types of comments to you and walk you through how to add comments to a PDF in 3 ways.

Tips for Adding Comments to PDF: Types of Comments

Basically, a comment in a file is a piece of text added to annotate the specific content, but you can add multiple types of comments to a PDF in fact. The types of comments in PDF include, but are not limited to:

  • Text
  • Sticky notes
  • Shapes with notes
  • Lines with notes

To add comments to PDFs efficiently, a handy PDF annotator is required. The software introduced in the post, such as SwifDoo PDF, is stable and easy to use. In addition to the listed comments, they also help add video, audio, and some other objects to PDFs for commenting. Read on to learn how-to.

Way 1: Add Comments to PDF with SwifDoo PDF

SwifDoo PDF is a small and fast software program to add comments to PDF documents. It enables you to comment on or annotate a PDF by adding sticky notes and carets in different colors, drawing shapes and lines, etc. You can use its 7-day free trial to add comments to PDFs for free. The PDF annotating software is available on all the recent versions of Windows, including Windows 7/8/10/11. Moreover, it has many other distinct features allowing you to convert, secure, make direct edits to PDFs, and more.

The three steps below show you how to add comments to a PDF easily using SwifDoo PDF.

Step 1: Drag and drop your PDF file into the free downloaded and launched PDF markup and annotation software;

Step 2: Click the Annotate tab on the top and choose a comment tool such as Note;

SwifDoo PDF add comments to PDF step 2

Step 3: Click a place on a PDF page and add a comment to the PDF in the pop-up box.

SwifDoo PDF add comments to PDF step 3

When needed, you can add comments to PDFs by directly typing text on them using the “Typewriter” tool. If you have added a shape, line, or highlight in PDF, double-click on it and a comment box will appear to allow for typing your comment. By hitting a comment in PDF within the PDF software, you have the option to change its color, opacity, line type, and other properties.

Tips: The “Attachment” comment tool under the "Annotate" tab makes it possible to add video (or audio) comments to PDF.

You can not only add comments to PDFs but also manage the comments in one place with SwifDoo PDF. To do that, click “Manage Annotations” in the “Annotate” section to open the comments panel in the left sidebar, then tap an icon or right-click on a comment to edit, reply, or delete it. Using the PDF software, you can print the added comments with your PDF file.

SwifDoo PDF - All-in-One PDF Software
  • Add comments, text boxes, watermarks, and signatures to PDFs
  • Edit, convert, compress, combine, organize, and protect PDF files
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Windows 11/10/8.1/7/XP

Way 2: Add Comments to PDF with PDF Expert

PDF Expert is a lightweight and simple-to-use PDF annotator to add comments to PDF documents. The free version of the software allows you to read, comment, and fill out forms in PDF. You can use your finger or the Apple Pencil to do the comment work. More advanced features such as converting PDFs require its pro version.

Learn how to add comments to a PDF for free with PDF Expert.

Step 1: Open your PDF file with the PDF annotator and choose Annotate on the top menu bar;

PDF Expert add comments to PDF step 1 | SwifDoo PDF

Step 2: Select Note, Highlight, Pen, or another tool in the drop-down toolbar;

Step 3: Tap a position on a PDF page and enter text in the comment box. Repeat the steps to add more comments to the PDF on your Mac.

Compared to desktop software, web applications sometimes may be more convenient to access. Find out which online tool to use and how it helps add a comment to a PDF in the coming part.

Way 3: Add Comments to PDF with PDF4me

Another free way to add comments to PDF is using an online tool, PDF4me. The software is developed to streamline your review work with a series of comment tools. It can be used to add pop-up comments, highlights, lines, and shapes in PDF documents. It also comes with PDF conversion, compression, combination, and a variety of other capabilities.

Take a quick look at how to add comments to a PDF online for free using this tool.

Step 1: Access the online tool in your browser and click Edit on the top of its website;

Step 2: Tap Select File to upload your PDF;

Step 3: Use the comment tools in the left sidebar to add comments to the PDF.

PDF4me add comments to PDF step 3 | SwifDoo PDF

The online PDF comment and annotation tool is easy to use but only allows you to process one file per hour. Compared to desktop software, it runs slower.


All three PDF software allow you to add comments to PDF documents for free quickly. Most of them let you add common comments such as bubble comments. Among them, SwifDoo PDF enables you to add much more types of comments, including videos and audio. Importantly, after comment, you can review and manage all of them in the sidebar quickly. Get it for a 7-day free trial and you are able to test all the features.

With respect to how to add comments on PDFs using other tools, navigate to SwifDoo PDF's blog page to get more top PDF annotators on the market.


Q:How do you add comments to PDF in Adobe Reader PDF program?

To add comments to a PDF file in Adobe Reader, open your PDF with the software, select "Tools" > "Comment", and use the comment tools in the pop-up toolbar to do your work.

Q:Why can't I add comments to a PDF?

If you can't make comments on a PDF but can do that with some other PDFs, it is probably because the PDF file is password protected from unauthorized editing. Regarding how to add comments to a secured PDF file, enable editing by offering the correct password in PDF software or remove the password from the protected PDF. Then you can add comments to the PDF without a hassle.

Q:Can people see comments in PDF?

After you add comments to a PDF and send the PDF to others, the recipients can see the comments just like you can in a PDF annotator. Therefore, multiple people can add comments in a PDF for collaboration. Please note that the built-in PDF reader in any browser won't let you check the audio or video comments.

Charlotte has been in the software industry for 8+ years. She works for AWZWARE now as a passionate writer. She is good at providing simple guides to use various video, office and entertainment software. Charlotte also recommends many other useful tools to make your work and life easier. A food lover too.

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