How to highlight a PDF online
Studying a contract, marking a lease, or annotating notes? You can drag highlights onto any PDF in your browser and download the marked-up copy — free, no account, nothing uploaded.
Just a web browser and your PDF. Everything happens on your device.
Highlight a PDF in 5 steps
-
Open your PDF
Go to the PDF editor and open your file (click Open PDF or drag it in).
-
Choose the Highlight tool
Select Highlight in the toolbar (or press H).
-
Drag across the passage
Click and drag over the text you want to mark. Release, and the highlight is placed.
-
Pick color and opacity
Use the panel to switch colors (yellow, or any color you like) and adjust how strong the highlight is.
-
Export the marked-up PDF
Click Export to download a copy with your highlights baked in.
Highlights use a “multiply” blend — like a real highlighter, the words underneath stay crisp. Use different colors for different topics.
Frequently asked questions
Can I remove or move a highlight?
Yes — switch to the Select tool, click the highlight, then drag it or delete it.
Does highlighting change my original file?
No. You download a new marked-up copy; the original stays untouched.
Can I highlight in different colors?
Yes — pick any color and opacity in the properties panel.
Can I highlight on my phone?
Yes — drag with your finger, same as on desktop.
Why a highlight beats a scribble
Highlighting sounds trivial until you’re the person on the other end of the document. When you send a lease back with the rent, the deposit, and the break clause each marked in their own color, the other side knows exactly where to look — no covering note required. A wall of underlines or freehand circles does the opposite: it signals “something here” without saying what, and it usually photocopies into an unreadable mess.
The habit that pays off is using color with intent — yellow for “read this,” a second color for “I disagree,” a third for “needs a number filled in.” Do that consistently and your marked-up PDF becomes a map anyone can follow. Because the highlight sits on top of the text with a multiply blend, the words underneath stay perfectly legible; you’re drawing attention, not painting over the content.
And because you’re always working on a copy, you can be generous. Mark a document up heavily for your own study, export that version, then produce a cleaner one to share. The original never changes, so there is no risk in experimenting.
This guide is for general information. AmigoPDF is a free, in-browser utility; always keep a copy of your original files.