Mark a PDF for review without changing its original wording
Annotate PDF adds a coloured highlight, outline box or underline at a measured position. It is useful for drawing attention to a heading, a section to review or a value that needs checking. You choose the page positions, shape dimensions, colour and opacity; the tool does not select words automatically.
These marks become ordinary page drawing content, not interactive comments. They have no reply thread, author field or comment-pane controls. The PDF is not converted into page images, and covering a sentence does not remove the original sentence from its content. Use marks to communicate attention, never to hide information before sharing.
Choose a mark that communicates your intent
| Your situation | Recommended approach |
|---|---|
| You want to draw attention to a line or short section. | Use a low-opacity highlight and check that the original text remains legible. The rectangle follows your measurements, not the words, so review where it begins and ends. |
| A barcode, signature or small number must remain unobscured. | An outline box can leave the interior clear. Leave room around the content and check the border does not intersect something important. An underline is another option when its placement is precise enough. |
| You need written feedback, editable comments or redaction. | Use Edit PDF for a visible text note, or a commenting editor for threaded feedback. Use a separate redaction workflow for sensitive content; a solid highlight is only a cover, even at 100% opacity. |
Highlight the first sample page's heading
The five-page device-document-lab.pdf has a heading near the top of each page. This example marks only page 1 so the other four pages provide an unchanged visual comparison.
- Choose device-document-lab.pdf and select Load PDF pages. Set Pages to update to 1 and Annotation style to Highlight.
- Set From left to 10 mm, From top to 18 mm, Width to 180 mm and Height to 12 mm. Set Opacity to 35% and retain the amber colour #b7791f.
- Select Apply annotation, then Download PDF. The result should report 5 PDF pages and 1 updated page.
- Open the downloaded file beside the original. Inspect the translucent band across the first heading, then check pages 2–5 for an unwanted repeat. Try selecting the original heading's text to understand why highlighting is not redaction.
Expected result. The output should retain five pages and add one translucent amber rectangle on page 1. The source heading remains underneath the mark. This example demonstrates a visible drawing overlay, not a removable comment object or a secure content-removal operation.
Check the downloaded result
- Inspect the download, not just the tool's thumbnails. The thumbnails show the input PDF; they do not update to preview the completed mark.
- Check every selected page. One configuration is applied at the same measured position on each one, even if their layouts or paper sizes differ.
- Check text readability and any barcode, field or signature close to the border. A mark can obscure meaning without deleting the information underneath.
- Keep the original and name the marked copy clearly. Its added drawings are not managed through a PDF viewer's comments list, and the tool does not retain an editable list of previous marks.
Troubleshooting
- The highlight misses the intended sentence.
Placement uses millimetres rather than text selection. Coordinates follow the visible crop area and supported page rotation, so a differently cropped page can need different measurements.
Try this: Adjust the offsets after inspecting the download. Start with one page before applying the same rectangle to several pages with different layouts.
- The annotation does not fit inside the page.
The width plus left offset, and the height plus top offset, must fit every selected page. A smaller page in the selection can cause the entire operation to fail.
Try this: Reduce the rectangle or offsets, or process differently sized pages separately. Verify the file-position numbers rather than relying on printed labels.
- A second attempt replaces the first attempted mark.
Start over returns to the settings for the selected input. It does not make the previous output the new source.
Try this: To accumulate different marks, download and inspect the first output, then choose that file as the next input. Keep the untouched original in case the accumulated drawings need to be discarded.
Limits and compatibility
- Shape behaviour
- One shape configuration is supported per run. Underline draws along the bottom of its measured rectangle; Height changes that line's vertical position and affects its bounded stroke thickness. There are no freehand strokes, sticky notes or drag-to-place controls.
- Compatibility and handling
- Processing is local and leaves the source file untouched. Protected inputs need unlocking first. File, page and output-size limits apply. Inspect existing interactive features and retain signed originals; adding visible marks is not a guarantee that a document's signature remains valid.
Your files and form values are processed on this device. Downloaded copies remain wherever you save them. See how to check local processing and our privacy policy for site data and optional services.
Common questions
- Can a recipient switch my highlight off in the comments pane?
- Not as an ordinary annotation: the new mark is page drawing content. That does not make it tamper-proof; an editor capable of modifying page content may change it.
- Will an opaque rectangle remove the text below it?
- No. A rectangle can hide the appearance while leaving underlying information in the PDF. Review the separate redaction tool's limitations before preparing a sensitive sharing copy.
Continue your document workflow
Maintained by Shakti Prasad Ram. Found a mismatch? Report the tool, browser and steps without sending a sensitive document. Back to the tool