Annotate PDF
Add highlights, sticky notes, and text boxes to a PDF, right in your browser — place, drag, resize, and undo, with a live HD preview the whole time.
Drop a PDF here, or click to browse
How annotating a PDF works
PDF annotation means adding highlights, notes, or text on top of a PDF page without changing the document's original content underneath. Pick a tool — highlight, sticky note, or text box — tap the spot on the page you want to mark, and it appears there instantly at a sensible default size. From there you can drag it anywhere on the page or resize it from its bottom-right handle, on a laptop trackpad or a phone screen equally well.
Everything renders and processes entirely in your browser: the page preview is drawn at a device-pixel-ratio-aware resolution so text stays sharp even when you zoom in, and the PDF itself is never uploaded to a server at any point. Sticky notes and text boxes are typed directly where you place them, and you can adjust a selected annotation's color, font size, or fill opacity from the panel that appears beside the page. Made a mistake? Ctrl+Z undoes it, and every placed item also shows up in the markup list on the side with its own delete button. Once your markup looks right, export bakes every highlight, note, and text box permanently into a new PDF you download straight to your device.
Common use cases
- Marking up a contract or agreement with sticky-note comments before sending it back for review
- Highlighting key passages in a research paper, textbook chapter, or report while reading
- Leaving feedback on a student's or colleague's draft without editing the original text
- Labeling sections of a scanned form or diagram with text boxes before printing or filing it
- Flagging clauses, numbers, or dates on an invoice or statement for a quick second look
Because it only adds markup on top of the page, this tool won't detect or select real text runs the way a word processor would — a highlight is a positioned translucent box, not a text-bound selection. If you need to change text that's already inside the PDF rather than mark it up, Edit PDF Text is the right tool for that instead.
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Annotate PDF — frequently asked questions
It draws a translucent, resizable highlight box wherever you place it — it doesn't detect or bind to specific words or lines of text. Drag it into position and resize it to fit the passage you're marking, and adjust its opacity from the settings panel once it's selected.
A sticky note shows as a small colored card with a drag handle and your note text inside — good for comments and review feedback. A text box places your text directly and permanently onto the page in your chosen color — good for labels, captions, or corrections. Both are typed and resized right on the page.
Yes. Every annotation can be dragged to a new position and resized from its bottom-right handle after you place it, on both mouse and touch. Ctrl+Z undoes your last change and Ctrl+Shift+Z redoes it — or use the undo/redo buttons above the page if you'd rather tap than remember shortcuts.
Yes — select it (tap or click it) and a settings panel appears in the sidebar with a font-size slider for sticky notes and text boxes, and an opacity slider for highlights and sticky notes. Changing the active color in the toolbar also recolors whatever's currently selected.
No — this tool only adds new markup on top of the page. It can't edit text that's already in the PDF. For that, use Edit PDF Text separately.
Yes. The page preview automatically fits your screen width, every control has a touch-friendly tap target, and dragging or resizing an annotation works the same way with a finger as it does with a mouse. Pinch-zoom is replaced with dedicated zoom buttons so you stay precise while marking up small text.
A password-protected file is detected immediately and you're pointed to Unlock PDF to remove the password first, since this tool can't read an encrypted file's pages. Very large files still work — you'll just see a heads-up that rendering and export may take a little longer, since everything is happening on your own device rather than a server.
No — nothing is saved automatically, on a server or otherwise. Export and download your annotated PDF before you navigate away or close the tab, or your placed markup will be lost.