HomeWinBuzzer TipsHow to Add Notes to a PDF for Free (3 Ways)

How to Add Notes to a PDF for Free (3 Ways)

We show you how to add notes to a PDF with Microsoft Edge, Adobe Acrobat Online, and the free PDF viewer UPDF.


If you work with PDF files regularly, you may want to know how to annotate and edit them effectively. PDF annotations are comments or notes you can add to a PDF document to provide feedback, suggestions, or instructions. In this blog post, we will introduce some of the most common types of annotations and edits that are supported by the PDF standard, and how you can use them with different programs.

The PDF standard defines 14 types of annotations that can be added to a PDF document. These are:

Text: A text annotation is a sticky note that appears on the page or in the margin. You can use it to add a comment, a question, or a reminder to yourself or others.
Link: A link annotation is a clickable area that takes you to another location in the same document, a different document, or a web page. You can use it to create cross-references, bookmarks, or hyperlinks.
Free Text: A free text annotation is a text box you can place anywhere on the page. You can add captions, labels, or callouts to your document.
Line: A line annotation is a straight line you can draw on the page. You can use it to mark boundaries, measure distances, or point out something important.
Square: A square annotation is a rectangle you can draw on the page. You can use it to highlight an area of interest, create a frame, or draw attention to something.
Circle: A circle annotation is an ellipse you can draw on the page. You can use it for the same purposes as a square annotation but with a different shape.
Polygon: A polygon annotation is a closed shape you can draw on the page with multiple vertices. You can use it to create custom shapes, such as arrows, stars, or symbols.
Polyline: A polyline annotation is an open shape you can draw on the page with multiple vertices. You can use it to create curves, splines, or paths.
Highlight: A highlight annotation is a transparent color overlay to apply to a selected text. You can use it to emphasize important words or phrases in your document.
Underline: An underline annotation is a horizontal line you can apply to a selected text. You can use it for the same purpose as a highlight annotation but with a different style.
Squiggly: A squiggly annotation is a wavy line you can apply to a selected text. You can use it to indicate your document's spelling errors, typos, or questionable content.
Strikeout: A strikeout annotation is a crossed-out line that you can apply to a selected text. You can use it to show deleted or replaced content in your document.
Stamp: A stamp annotation is an image you can place on the page. You can use it to add predefined stamps (such as “Approved” or “Confidential”) or custom stamps (such as your signature or logo) to your document.
Caret: A caret annotation is a symbol that indicates where text should be inserted in your document. You can use it to suggest additions or corrections to your document.

In addition to these annotations, you can also edit PDF files by adding, deleting, moving, resizing, rotating, cropping, or extracting pages; adding headers and footers; adding watermarks and backgrounds; adding bookmarks and attachments; adding form fields and signatures; encrypting and decrypting files; and more.

Many programs allow you to annotate and edit PDF files. Here we show you three practical tools you can use to add notes to PDFs for free on Windows and some examples.

How to Add Notes to PDFs with UPDF

A good alternative to uploading your PDFs online is using a free PDF reader such as UPDF locally, which offers tools to annotate PDFs. In addition to adding notes to PDFs, UPDF offers many other advanced features to visualize, convert, modify and convert your PDFs. Here we will give an overview of how to add notes with UPDF.

  1. Click the pen symbol in the left sidebar and choose the tool you want to use
    UPDF - Comment -
  2. Via the text bubble you can add a “Sticky note” in different colors
    UPDF - Comment - Sticky Note
  3. The Sticky Note will be available via a text bubble you can position freely in the PDF
    UPDF - Comment - Sticky Note - Note
  4. The “Text Comment” tool allows you to create text notes with different fonts, colors, text style, and font size
    UPDF - Comment - Text Comment
  5. You can position text comments freely with the mouse
    UPDF - Text Comment
  6. The “Textbox” tool is another way to add text to your document
    In comparison to simple text comments a textbox works better with whole sentences or even paragraphs as it offers a defined area to write on.
    UPDF - Textbox -
  7. Just draw the textbox where you want it with your mouse…
    UPDF - Textbox - Draw Box
  8. …then write your text and place the box where you want it to be located
    UPDF - Textbox with text
  9. UPDF also includes a great number of Stickers you can add via mouse click
    UPDF - Sticker
  10. Stickers can be resized and positioned freely
    UPDF - Sticker
  11. With the drawing tool you can annotate freely in different colors and thickness, and even opacity
    UPDF - Draw
  12. The drawing pen of UPDF is best for freestyle annotations but can also be used to highlight or mark certain sections or elements
    UPDF - Drawing

How to Add Notes to PDFs with Microsoft Edge

is not only a quick and easy way to open and view PDFs on Windows 11 / Windows 10. You can use preinstalled web browser also to add some notes to your PDFs. Here is how it works.

  1. Open the PDF and select the annotation tool you want to use
    Edge offers a drawing pen with flexible thickness and colors, a textbox tool, and a highlighter in the toolbar on top.
  2. Using the text tool you can choose text color, size and the distance between letters and position the text freely
    Microsoft Edge - Annotate - Text
  3. The highlighter also offers different colors, and you can choose the thickness
    The “Text only highlight” option lets you use the highlighter to mark exactly the relevant words.
    Microsoft Edge - Highlight

How to Add Notes to PDFs with Adobe Acrobat Online

Adobe Acrobat Online is a great alternative if you need more annotation and editing features. Here is how you can add notes to a PDF using this versatile web app after uploading your PDF.

  1. With the comment tool, you can either add comments directly as text on the PDF or via a comment bubble
    Both types of comments will be tracked and can be shown in the “Comments”-sidebar. Text comments or the comment bubble which opens the comment in the sidebar can be placed freely using your mouse.
    Adobe Acrobat Online - Add Comment
  2. There is also a “Highlight” tool with yellow color and an “Underline” and a “Strikethrough” tool
    Adobe Acrobat Online - Annotate
  3. The drawing tool allows you to draw with  different colors and thickness
    Adobe Acrobat Online - Draw
  4. With the “Textbox” tool you can add Text in different colors and font sizes
    Compared with “Text comments”, those annotations won´t be tracked as comments and will not be visible in the comments sidebar.
    Adobe Acrobat Online - Add Textbox
Markus Kasanmascheff
Markus Kasanmascheff
Markus is the founder of WinBuzzer and has been playing with Windows and technology for more than 25 years. He is holding a Master´s degree in International Economics and previously worked as Lead Windows Expert for Softonic.com.