Files never leave your device.How it works
How to annotate a PDF
- 1Drop your PDF above (or click to select).
- 2Pick a tool — highlight, pen, or text — and a color, then mark up the page.
- 3Click Apply and download the annotated PDF.
Frequently asked questions
- What can I add?
- Three things: translucent highlights (drag a box over text), freehand pen strokes for circling or underlining, and text notes you type anywhere. Each comes in six colors.
- Are the annotations permanent?
- They're baked into the page content so they show in every PDF reader and can't be toggled off. Keep a copy of the original if you might want an unmarked version.
- Does my file get uploaded?
- No. The PDF is rendered and marked up entirely in your browser — nothing is sent to a server, which matters for private documents.
Mark up a PDF like paper
Reviewing a document often means grabbing a highlighter and a pen. Annotate PDF brings that to the browser: drag a highlight over the important lines, use the pen to circle or underline freehand, and type notes wherever you need them — all without printing anything.
Highlights, ink, and notes in color
Switch between the highlight, pen, and text tools and pick from six colors. Highlights are translucent so the text underneath stays readable; pen strokes follow your cursor or finger; notes are plain text you place and edit. Move between pages and mark up as many as you like before applying.
Notes and limits
Annotations are flattened into the page, so they display everywhere and can't be edited later by a reader — keep the original if you need a clean copy. Everything runs on your device, so private documents stay private. To permanently black out content instead of marking it, use Redact.
How annotations are drawn
The PDF page is rendered to a canvas in your browser, and every highlight, pen stroke, and note is captured as its own shape with a position and color before being composited back into the page as real PDF content on save. That's why annotations show up identically in Acrobat, Preview, or a phone's PDF viewer — they're not a proprietary overlay that only HivePDF understands, and there's no plugin or account needed to view them later.
When markup makes sense — and when it doesn't
Annotate PDF is built for reviewing existing content: marking up a contract draft, circling an error in a diagram, or leaving a note for a colleague. It's not an OCR tool, so a highlight on a scanned page just draws a colored box in that spot rather than selecting underlying text — run OCR first if you want the highlight to align with real, searchable text. To cover something up so it can never be recovered, use Redact instead, since a highlight only sits on top of the text and doesn't remove it.