Marking up without an app
Reviewing a document usually means highlighting a few passages, circling something and writing a note beside it. Doing that normally means a PDF application, and on a shared or locked-down machine, or a phone, you may not have one that can write to the file.
This does it in the browser. Highlights, pen strokes and text are drawn onto the page and written back into a real PDF that opens anywhere.
Drawn on, not attached
PDF has two ways to add a mark. It can be an annotation object— a comment layered above the page that a reader can show, hide or delete — or it can be page content, drawn into the document itself.
This tool draws page content. That means your marks travel with the file and cannot be toggled off by whoever opens it, which is normally the point of marking a document before sending it. It also means they are permanent, so keep the original if you might want a clean copy.
The text layer survives
Everything is drawn as vectors on top of what is already there. The original content is not touched and nothing is rasterised, so the annotated file stays searchable and selectable, and stays about the same size.
That is the right trade for annotation and exactly the wrong one for hiding information — which is worth stating plainly, because the two look identical on screen.
A highlight is not a redaction
Drawing over text does not remove it. Even a solid black box leaves the text underneath, still selectable and still returned by any extractor. People leak documents this way constantly.
If your goal is to take something out rather than draw attention to it, use Redact PDF, which rebuilds each page as an image so the content is genuinely gone. This tool is for marking up; that one is for removing.
Common uses
- Highlighting the clauses that matter in a contract
- Marking corrections on a draft before sending it back
- Circling a figure in a report and writing a note next to it
- Signing off a document with a handwritten tick or initials
- Marking up a scan, where there is no text to select
Privacy
The document stays on your device throughout. Contracts and drafts under review are exactly the files that should not be uploaded to have a few lines drawn on them.