slicerflowAnnotate PDF
Annotate PDF

Annotate a PDF
add comments

Mark up any PDF with comments of different styles — sticky notes, highlights, underline, strikeout, text boxes, shapes, arrows and freehand ink, in any colour. It all runs in your browser.

No account · no install · nothing uploaded · MIT open source

# annotate a PDF — 3 steps
1. Import   drop your PDF
2. Mark up   note · highlight · shape · arrow
3. Export   download the annotated PDF

Open the studio's 📄 PDF tab to start.

How to annotate a PDF

Add comments and markup, then export them baked into the file.

Import the PDF

Drop your PDF and open the page you want to comment on.

Add annotations

Pick a tool — note, highlight, underline, strikeout, text, rectangle, ellipse, arrow or ink — choose a colour, and draw on the page.

Export

Click Export PDF to download the file with your annotations flattened in.

Why annotate PDFs with slicerflow

More slicerflow PDF tools

Annotate PDF — FAQ

How do I annotate a PDF?

Open the PDF tab, import your PDF, pick an annotation tool (note, highlight, shape, arrow and more), choose a colour, draw on the page, then Export PDF.

What annotation styles are available?

Sticky notes, highlight, underline, strikeout, free-text boxes, rectangles, ellipses, arrows and freehand ink, in any colour.

Are the comments saved into the PDF?

Yes. On export the annotations are flattened onto the pages, so they show in any PDF viewer.

Is annotating a PDF private?

Yes. It runs entirely in your browser, so your document is never uploaded.

Comment on your PDF

Add notes, highlights and shapes, then export the annotated PDF — free.