Highlight a PDF online
Mark important lines in research papers, contracts and study material, just like a highlighter pen on paper.
- No upload: 100% in your browser
- No sign-up
- Free to use
PDF, JPG or PNG · processed on your device, never uploaded
How to highlight PDF
It takes less than a minute with PDFHeron.
Open the PDF
Drop the document onto this page.
Choose Highlight
Drag across the passage you want to mark.
Pick a color
Choose yellow, green, blue, pink, orange or any custom color.
Save
Highlights are saved into the PDF and show up in any reader.
Highlights that look right
Highlights are blended with the page like real ink, so the text underneath stays perfectly readable on screen and in print.
Why use PDFHeron to highlight PDF?
Private by design
PDFHeron processes files on your device. No uploads, no cloud copies, no one else ever sees your documents.
Real editing
Change existing text and delete content from the file itself, not just paint boxes on top of it.
Instant & offline-ready
No queues or upload waits. Big documents open in seconds, and editing keeps working without a connection.
True redaction
Redacted areas are permanently removed from saved PDFs, so hidden text can’t be copied back out.
Standard PDF output
Saved files are regular PDFs with selectable text that open in Acrobat, Preview, Chrome and every other reader.
Free, or $2 once
Use every tool for free. Remove the footer forever with a one-time Pro license, with no subscription.
Highlight PDF: FAQ
Can I use different colors?
Yes. Choose from the preset palette or any custom color, and adjust opacity.
Can I remove a highlight later?
Select it and press Delete, or use Undo.
Does highlighting work on scanned PDFs?
Yes. Highlights are drawn over any page content.
Edit your PDF now. It’s free
No sign-up, no upload, no waiting. Open a file and start editing in seconds.
Open the PDF editor