Add Notes to PDF: Sticky Notes, Text Boxes, or Highlights?

A note in a PDF is not the same as editing the document itself. It's a separate layer sitting on top of the page — like a sticky note on a printed document. It doesn't change the original text; it just marks it up for discussion.

And here's where it gets interesting: not all "notes" are the same. You have sticky notes, text comments, text boxes, callouts, highlights, drawings, shapes — each serves a different purpose.

This guide covers everything you need to know about adding notes to a PDF. Whether you're a first-time user trying to leave simple feedback, a team lead coordinating a review, or someone looking for a free alternative to Adobe Acrobat — you'll find the answer here.

Two Types of Notes — Which One Do You Need?

Before you start, it's critical to understand that "adding a note" can mean different things depending on what you're trying to achieve.

Sticky notes and text comments are the most common types of "notes" — they sit on top of the page and don't change the original content. So let's continue to see how to choose tools to add notes to PDF: online options or other built-in tools, or professional desktop software?

Adding notes to a PDF is straightforward once you know what type of note you need — and which tool fits your workflow. Below, you can choose tools according to your true needs: online or offline?

How to Add Notes to PDF Online (Free Included)

Tailored for students and casual users handling one-time PDF markup tasks who prefer zero software installation, online PDF annotation tools excel at quick edits on single, non-confidential files: users upload documents to cloud servers, add various markups via an in-browser editor, and export the annotated PDF locally upon completion.

The comparison table breaks down top online PDF annotators: Smallpdf is the best all-in-one option with full highlight, drawing and sticky note tools; Xodo provides complete markup without Adobe Acrobat; LeedPDF and GroupDocs.Annotation leads in privacy with local processing. Most free tools enforce file size limits, so confirm restrictions before uploading large files.

Online PDF note-taking features simple, uniform operations, yet picking the right tool greatly impacts your experience. The universal steps are: visit the editor page, upload PDFs, select markup tools, adjust formatting, save and download the edited file.

Smallpdf Step-by-Step Example

1. Access Smallpdf’s Edit PDF page
2. Upload files via drag-and-drop or "Choose File"
3. Pick tools: add text boxes, sticky notes, colored highlights, freehand sketches, or shape arrows
4. Modify color and size settings as needed
5. Tap Finish and export your annotated PDF

Common Limitations of Online Tools

All web editors require cloud uploads, risking sensitive data leaks. They rely on Wi-Fi with no offline mode, cap maximum file sizes, lack advanced annotation functions, and lock collaborative editing behind paid plans. Let's see how the desktop software performs.

How to Add Notes to PDF Offline (Full Notes Suite)

Designed for professionals and regular annotators handling confidential files and advanced markup tasks, desktop PDF editors keep all documents stored locally without cloud transmission or third-party servers, making them the sole reliable choice for scenarios requiring strict data privacy and full-featured annotation tools.

The comparison table evaluates leading offline PDF annotators: UPDF delivers top overall value with a one-time cross-platform license and complete annotation toolkit.

Long-term pricing clearly favors one-time purchase or free tools. Adobe’s recurring fees balloon to $1,200 over five years, and Foxit accumulates $445. UPDF locks in a single flat fee permanently.

Add Notes to PDF with UPDF

As the most cost-effective desktop solution, UPDF offers simple steps to add advanced PDF annotations offline. You just go to the Tools in the left corner and enter Comment mode, then you can select the tools listed in the picture below and choose to use them.

Add Sticky Notes to PDF Via Adobe Reader

Adobe Reader is the most popular PDF reader at the moment. Many users also want to know how to add sticky notes to PDFs with it. So we also show the guide here.

Step 1. Open Adobe Reader after downloading it on your computer. Go to "File" > "Open" to choose the PDF file that you want to add sticky notes to.

Step 2. Click on the "Sticky Note" icon at the top menu, and put it in the place where you want to add it to. Now, you can enter the notes here. When it is done, you can click "File" > "Save" to save all sticky notes on your PDF.

Add Notes to PDF in Microsoft Edge

If you are someone who does not want to download desktop tools, you can use Microsoft Edge to add notes to a PDF. It is also very easy. Here is the guide.

Step 1. Right-click the PDF file, choose "Open With," and select "Microsoft Edge" to open the PDF you want to add notes to in Microsoft Edge.

Step 2. Now, select the content you want to add a note to, then find the "Add comment" icon and click it.

Step 3. Now, you can add content. Once it is done, click on "√"to save the notes to PDF. After finishing adding notes to PDF, you can click the "Save" or "Save as" icon at the top-right menu to save it.

Add Notes to PDF in Preview

If you have a Mac computer and want to know how to add notes to a PDF with Preview, you can check this guide.

Step 1. Right-click on the PDF file on your Mac. Then, select "Open With" > "Preview" to open the PDF.

Step 2. Now, find the pencil icon and click on it to show all menus. Click on the "A" with a rectangle to add a note to the PDF here. When everything is ok, you can go to "File" to save all your changes.

What's Your Purpose of Adding Notes to PDF?

The purpose of adding notes to PDF determines the methods we need to accomplish this.

1: Add a movable, collapsible text box anywhere on the page for writing longer comments or descriptions.

2: Enter text directly into a designated area of ​​the PDF (such as a blank area in a form) to simulate typing.

3: First, highlight a section of text, then add a note or explanation to that highlighted text.

4: On touchscreen devices, use a stylus or your finger to directly handwrite text or symbols on the page.

5: Quickly mark statuses such as "Needs modification", "Approved", "Important", etc.

6: Want to extract the notes scattered across various pages and create a separate document for easier review or organization.

No matter your purpose or where you encounter difficulties, you can find solutions below.

Final Words

Adding notes to PDF is very important if you use PDF files frequently for reading, collaborating, and sharing. Good tools can make all the difference.

UPDF is a better choice as it has different ways to add notes to PDF, allows you to customize the notes, and adds notes to PDF on Windows, Mac, Android, and iOS devices. You can download UPDF via the button below to test.

This guide focuses specifically on adding notes to PDFs as part of PDF annotation. If you're looking for a complete guide on all types of PDF annotations — highlights, sticky notes, drawings, stamps, text boxes, callouts, and more — check out our full pillar guide: How to Annotate PDF.