Underline Text
Draw underline lines under text in a PDF — for emphasis, marking insertions, or grammar-style annotation.
1. Upload your file
How does the Underline Text work?
Draw underline lines just below specified rectangles on a PDF — useful for emphasising key terms, marking insertions in redline editing (green is the convention), or stylistic annotation. The line is drawn 2 points below the bottom edge of each rectangle so it appears under the text rather than on top of it.
🔒 Security & Privacy
All processing happens on your device. Your files never leave your browser, never touch our servers, and are not stored anywhere. Close the tab and the file is gone.
📱 Use it on any device
Works in any modern browser — Mac, Windows, Linux, iPhone, Android, and tablets. No installation, no app to download. Just open the page and start.
⚡ Quick & easy
Drag, drop, click. Most files process in seconds, not minutes. No watermarks added to your output, no per-day limits, and the tool always shows the result before asking you to download.
🎁 Always free, no signup
Free to use, every time. No account creation, no email required, no “trial” that converts to a paid plan. We make money from ads so you don’t have to pay.