This guide shows you how to highlight and annotate PDFs directly in Chrome using the Web Highlights browser extension. No extra software needed — just open a PDF and start marking it up.
How to Annotate a PDF in Chrome
Chrome can open PDFs natively, and with Web Highlights installed you can highlight and annotate them directly. Here's how:
- Open any PDF in Chrome — navigate to an online PDF link, or drag a local PDF file into a Chrome tab.
- Web Highlights detects the PDF and shows a "Highlight this PDF" banner at the top. Click it, or click the Web Highlights extension icon in your toolbar.
- The PDF opens in the Web Highlights viewer. Select any text to see the highlight popup — pick a color to highlight.
- Click any highlight to add notes, change the color, or add tags for organization.
- Use the sidebar to see all your highlights, export them, or search through your annotations.
Tip: For local PDFs, make sure you've enabled "Allow access to file URLs" in the extension settings (chrome://extensions → Web Highlights → Details → toggle on).
What You Can Do with PDF Annotations
Once you've opened a PDF in the Web Highlights viewer, you get a full annotation toolkit:
- Highlight in multiple colors — Color-code your annotations to separate key points, questions, definitions, and evidence.
- Add notes to any highlight — Click a highlight to attach your own thoughts, summaries, or reminders.
- Tag and organize — Add custom tags to highlights for easy filtering and retrieval later.
- Export your annotations — Send highlights and notes to Notion, Capacities, Markdown, HTML, or PDF.
- Sync across devices — All annotations are stored in the cloud and accessible from any device through the web app.
For the full details, see our PDF highlighting documentation.
Good to Know
- Text-based PDFs only — Scanned PDFs without a text layer can't be highlighted. Run them through an OCR tool first.
- No image highlights in PDFs — Image highlighting works on web pages, but PDFs are text-only for now.
- Local PDF paths matter — Highlights on local PDFs only persist if the file stays at the same location on your device.
Chrome's Built-in PDF Tools vs. Web Highlights
| Feature | Chrome | Web Highlights |
|---|
| Text highlighting | ❌ | ✅ Multiple colors |
| Add notes to highlights | ❌ | ✅ |
| Tags & organization | ❌ | ✅ |
| Export to Notion, Markdown, etc. | ❌ | ✅ |
| Sync across devices | ❌ | ✅ |
| Works across browsers | ❌ | ✅ Chrome, Edge, Firefox, Brave, Opera, Vivaldi |
Try Web Highlights as Your PDF Annotator
Highlight and annotate any PDF right in your browser — free, no sign-up required.
Install Web Highlights Want a deeper walkthrough with screenshots? Check out our full blog post: How to Annotate a PDF in Chrome.
Need help with another browser? Check out our other browser tutorials.