How to Write and Mark Up a PDF: Highlight, Note and Draw

Reviewing a document, you want to highlight what matters, jot a note in the margin or box a clause. Markup PDF lets you add highlights, drawings, boxes, arrows and text notes — without erasing the text and without your file leaving your device.

How to Write and Mark Up a PDF: Highlight, Note and Draw

Reviewing a contract, an assignment or a report, you want a pen in hand: highlight the key sentence, jot a note, box a clause, point with an arrow. Markup PDF lets you do this in the browser, with your file never leaving your device.

Which markup tools are there?

  • Highlighter: paints over text semi-transparently; the text below stays readable.
  • Pen: freehand drawing, with a straight-line mode too.
  • Box and Arrow: frame a region or point to it.
  • Text: write a note in the margin or on the document.

Step by step: mark up a PDF

  1. Open the PDF: Drag and drop or choose the document you want to mark up.
  2. Pick a tool and color: Highlighter, pen, box, arrow or text; then choose a color and thickness.
  3. Draw on the page: Drag to mark. Marker/pen offer a «Straight» mode to draw cleanly over lines of text.
  4. Edit and download: Use «Select» to move, resize or recolor a mark; undo with Ctrl+Z. Then «Apply & download».

Marks are added ON TOP of the document; existing text is never removed or changed. Highlighter and pen are semi-transparent, so the text below stays readable.

Markup PDF — Mark up your document with highlights, drawings and notes — on your device, no sign-up.

Handy for review and collaboration

Download the marked-up PDF and share it by email; the other side sees your notes in any PDF viewer. If you also need a signature use Sign PDF, and for text corrections use Edit PDF on the same document.

Markup, editing and redaction are not the same

The three look similar but their results differ completely, and picking the wrong one causes problems.

  • Markup: adds a layer over the document. The text underneath stays readable and searchable. This is the right choice for review and feedback.
  • Editing: actually changes the text in the document. This is what you need to correct a wrong date or amount.
  • Redaction: removes the text from the document. It is the only correct method for hiding personal data; drawing a black box is not enough.

Making review notes understandable

Markup someone else will read is different from a note to yourself. A paragraph that is only highlighted leaves the reader asking what about it. A one-sentence note noticeably reduces the number of rounds. Using colour to carry meaning helps too — yellow for «attention», red for «must change», green for «approved». Explaining the scheme in a note at the start saves the other side from guessing.

A practical order for contract review

When reviewing a legal or commercial text, following a set order rather than marking as you go both speeds up the review and prevents omissions: mark everything containing an amount, date or duration first; then the sentences that create obligations; and last the wording you find unclear. That three-pass sweep is more reliable than reading end to end once.

Sharing a marked-up document

Because marks are written into the document, the recipient sees your notes in any viewer without special software. That does not mean they cannot be removed; if a clean version is needed, it has to be regenerated from the original. Saving the marked-up version under a new name and keeping the original clean is the good habit here.

How it looks in print

A highlight that reads comfortably on screen can become a grey band over the text in black-and-white print. If the document will be printed, prefer light colours and put the important information in the note rather than the colour. In greyscale colours converge, so marks distinguished only by colour lose their meaning on paper.

Frequently Asked Questions

Can marks be removed?

In the file you download, the marks are written into the document. For a clean version you need to start again from the original, which is why keeping a clean copy matters.

Can I add notes to a PDF someone else marked up?

Yes. Layers added over the document accumulate, so you can add your own notes and download a new version.

Can I mark up a scanned document?

Yes. Because markup draws over the page, it works on scans too. If you want to draw neatly over lines of text, making the document searchable first makes it easier.

Do marks increase file size?

Drawings and notes are small vector objects; the increase is negligible in most documents.

How do I write on / mark up a PDF?

Upload the PDF to the Markup tool, pick highlighter/pen/box/arrow/text and drag on the page. Click «Apply & download» to get the marked-up PDF. Everything runs in your browser.

Does highlighting over text erase it?

No. Marks are added on top; existing text is not removed. Highlighter and pen are semi-transparent, so the text below stays visible.

Can I undo or edit a mark I made?

Yes. Undo with Ctrl+Z; use the «Select» tool to move, resize or recolor a mark afterwards.