PDF Annotator
About the PDF Annotator
The PDF Annotator tool draws a colored, semi-transparent highlight rectangle onto a specific page of a PDF, letting you call attention to a particular area — a clause in a contract, a figure in a report, a section that needs review — without altering the underlying text or images beneath it. This is the digital equivalent of using a highlighter pen on a printed page, applied directly to a PDF you're reviewing.
You specify the page number, the X and Y position of the highlight's top-left corner, its width and height, and a color of your choosing using the built-in color picker. The tool then draws a rectangle at 40% opacity in your chosen color directly onto that page, letting the original content show through while still clearly marking the highlighted region. Because the highlight is a distinct visual layer, it doesn't interfere with or obscure the text and images it sits above.
This is a practical tool for document review workflows: marking up a contract clause that needs a second look before signing, highlighting a data point in a report during a team review, flagging a section of a form that still needs to be completed, or drawing attention to a specific part of a diagram or image embedded in the PDF. Because you control the exact position and size, you can highlight anything from a single word to an entire paragraph or table.
As with the PDF Editor tool, positioning is coordinate-based, so you may need a couple of attempts to land the highlight exactly where you want it — add it, review the result, and adjust the X, Y, width, and height values as needed on a follow-up pass. For a complete review-and-mark-up workflow, combine this tool with the PDF Editor to add explanatory text notes near your highlights, or the Add Stamp tool if you need a more official-looking marker like APPROVED or REJECTED alongside your highlighted sections.
When highlighting text you want to draw attention to, it generally works best to make your rectangle slightly larger than the text itself rather than trying to match it pixel-perfectly, since a small margin of highlight color around the target text reads more clearly than a tightly-fitted box that might clip the very edges of the content you're trying to emphasize. If you're marking up a document for a team review process, agreeing on a shared color convention beforehand — for example, yellow for "needs discussion" and green for "approved as-is" — makes the highlights immediately meaningful to anyone reviewing the document afterward, rather than requiring a separate explanation of what each color means.
Because the highlight becomes part of the page's actual content rather than a toggleable annotation layer, it will display consistently for anyone who opens the document afterward, in any viewer, without depending on annotation support being enabled or even present in whatever software they happen to be using. This reliability makes it a solid choice specifically for markup that needs to remain visible no matter who opens the file or what tool they use to do it.
Step-by-Step Instructions
- Upload your PDF into the drop zone.
- Enter the target page number.
- Set the X and Y position for the highlight's top-left corner.
- Set the width and height of the highlight rectangle.
- Choose a highlight color using the color picker.
- Click "Add Highlight" to apply it.
- Your browser downloads the result automatically as annotated.pdf.
Benefits & Use Cases
- Marks up key sections of a PDF without altering the original content
- Fully customizable position, size, and color
- Semi-transparent overlay keeps underlying text legible
- Ideal for contract review, report markup, and form flagging
- Works well alongside the Editor and Stamper tools
- Fast, one-click, fully private processing