Annotate PDF

How do I annotate a PDF?

Press Choose a PDF to annotate and every page opens below the title. Pick Highlight and drag across words, or pick Note, Text, Pen, Marker or Shapes and mark the page. Click any mark to change its color, add a comment or delete it. Press Save annotated PDF, then Download.

1. Press Choose a PDF to annotate. The Full screen button gives the pages the whole window.
2. Pick a tool along the top: Highlight, Underline, Strikeout, Marker, Pen, Note, Text or Shapes.
3. Set the color, opacity and line width in the bar above the pages, then mark the page.
4. Pick Select and click a mark to move it, restyle it, comment on it or delete it.
5. Press Save annotated PDF, then Download.

How do I highlight text in a PDF?

Pick Highlight and drag from the first word to the last, as you would select text. The tool reads where each word sits in the PDF and places one highlight piece per line, covering whole words. A single click highlights one word. On a scanned page with no text, drag a box or use the Marker.

Underline and Strikeout work the same way. Highlights are drawn in multiply mode, so black text stays black under the color, and the opacity menu sets how strong the color is. The highlighted words are kept with the mark and appear in the Comments list. To change the words themselves, use Edit PDF instead, which rewrites the page.

How do I add comments to a PDF?

Pick Note and click the page: a sticky note icon appears with a box to type your comment. Pick Text to type a comment directly on the page instead. Any highlight, drawing or shape can carry a comment too: select it and press the comment button in its small bar. Your name can go on every comment.

Set your name under Options; it is saved in this browser only and written into each annotation as its author, which PDF readers show next to the comment. Sticky notes keep their text in the note itself (the PDF's Contents entry), so a reader shows it when you open or point at the icon.

Can I draw on a PDF?

Yes. Pick Pen to draw freehand with a mouse, finger or stylus, or Marker for a wide see-through stroke that works like a highlighter on scans. Shapes adds rectangles, ellipses, lines and arrows. Each stroke and shape can be moved, recolored, made thicker or thinner, and given a comment after you draw it.

On a phone, pick a drawing tool and draw with one finger; pick Select again to scroll the pages with one finger. Two fingers pinch to zoom.

Will my annotations show in other PDF readers?

Each mark is saved with its own appearance drawing, as the PDF standard (ISO 32000) describes, so a reader can show it without drawing it itself. We checked saved files with PDF.js, the library behind the Firefox viewer: it read all ten kinds of mark back with their comments and drew every one. The table lists each annotation type.

A highlight also carries QuadPoints, the corners of each highlighted line, so an app that redraws the highlight itself puts it in the same place. A comment adds only its own text to the file.

What does flattening annotations do?

Flattening draws each annotation into the page itself and removes the annotation, so the marks look the same in every reader and print the same way, but nobody can edit, move or reply to them afterwards. Tick Flatten annotations into the page under Options before saving. Annotations already in the file are flattened too.

In the build test, all 9 marks above were flattened and 9 annotations were drawn into the page. Flattening rewrites the file, so a digital signature in it stops being valid; keep the unflattened copy if you need either. Flatten PDF does the same for a file someone else annotated, and for form fields.

How do I export the comments from a PDF?

Press Comments in the toolbar to list every comment on every page, the ones you added and the ones already in the file. Press Export .txt to save them as a plain text file, page by page, with the type of mark, the author, the highlighted words and the comment text. Click an entry to jump to it.

Is it safe to annotate a PDF online?

Annotating sites that work on a server upload your document to their servers. This page reads the PDF in your browser, draws the marks on your device and saves the result straight back to it; nothing is sent anywhere. Your marks are also kept in this browser while you work, so a refresh does not lose them.