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Draw on a PDF — Freehand Pen, Shapes, and Annotations

Mark up a PDF like you would with a highlighter on paper: circle a figure, arrow to a paragraph, sketch a margin note, or underline a key phrase. WT-PDF's Draw tool gives you a freehand pen plus rectangles, circles, lines, and arrows — all with configurable color and stroke width, all baked into the PDF on download.

Open the editor

How to draw on a PDF

Open wt-pdf.com and drop in your PDF.
Click the Draw tool (palette icon) in the toolbar.
Pick your tool from the dropdown: Pen (freehand), Rectangle, Circle, Line, Arrow, or Callout.
Adjust Color and Width.
Drag on the page to draw. Use "Undo stroke" to remove the most recent freehand stroke.
Download. Every stroke is baked as a native PDF line path.

What the pen tool is good for

Feedback on documents — circle issues, add margin notes, draw arrows to paragraphs.
Approvals — check boxes, initial pages, draw a quick OK ✓.
Tutoring & teaching — explain a diagram, box a formula, handwrite an answer.
Engineering / architecture markup — flag a measurement, note a revision on a plan set.

Are the strokes really part of the PDF?

Yes. Strokes are rendered during editing as an SVG overlay for responsiveness, but on download each stroke is converted into a sequence of l line segments in the PDF content stream — the same primitives Acrobat would use. They render identically in every viewer.

FAQ

Can I use a stylus or Apple Pencil?

Yes. Pointer events support stylus input on supported devices. Draw with pressure-independent strokes (pressure sensitivity is not yet captured).

Can I erase individual strokes?

The "Undo stroke" button removes the most recent stroke on the current page. For older strokes, use the main Undo (Cmd+Z) which reverts the PDF state.

Does drawing enlarge the file much?

Negligibly. Each stroke is just a few bytes of coordinate data, not a raster image.

Is the stroke smoothed?

We capture every pointer-move sample and render them as joined line segments with round line caps. For typical hand-drawn speeds, this looks smooth without distortion.

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