PDF Underline OnlineNEW
Draw clean text underline styles on matches, keywords, or customized page selections offline.
Drag & drop files to underline
or click to browse from your device
How PDF Underline Works
Easily markup and emphasize key concepts in your PDF documents.
Upload PDF
Select and load your PDF file directly into your browser window securely.
Apply Underlines
Search for specific words to underline them automatically, or draw custom lines by dragging.
Download Markup
Export the newly annotated PDF immediately without formatting loss.
Why choose our markup editor?
Underline text elements in seconds using our intelligent search indexing or freehand vector strokes.
Search & Auto-Underline
Type keywords or phrases to instantly highlight all matches across all pages simultaneously.
Adjustable Styling & Colors
Choose custom line weights, select from a professional palette, or pick any hex color.
Completely Client-Side
Your documents never touch a web server. All parsing, rendering, and rendering tasks run in memory.
Frequently Asked Questions
Common queries regarding client-side PDF text markups.
Q.Will this affect the original text layers?
No, the underlying text remains copyable and searchable. The lines are vector objects layered precisely relative to text bounds.
Q.Can I choose different colors for different pages?
Yes, you can customize individual line colors, positions, and thickness properties separately for any selection.
Q.Is my data secure?
100% yes. All operations are run locally within your web browser cache. No PDF content is sent to any server.
Q.Can I remove annotations after drawing them?
Yes, select any underline in the preview pane or the sidebar checklist and click the delete icon to remove it.
How Underline Tool Works
Our high-performance online utility runs entirely client-side, processing your files securely and instantly inside your web browser. For related functions, you can also use our Strike Through and All Tools utilities.
Upload PDF
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Select Text
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Apply Underline
Step-by-step interactive processing designed for simple, fast, and high-fidelity execution.
Annotation Features
Designed for professional results, privacy, and maximum compatibility across all modern desktop and mobile browsers:
Custom Styling
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Color Options
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Batch Process
Full digital precision and optimized performance with zero server-side latency or external data transfers.
100% Offline
Full digital precision and optimized performance with zero server-side latency or external data transfers.
Frequently Asked Questions About PDF Underline
Is this PDF underline free?
Yes. Add unlimited underlines with no registration.
Can I customize the styling?
Yes. Custom colors, line styles, and thickness for underline annotations offline.
Does it batch process?
Yes. Apply underlines to multiple text segments across documents in bulk.
Do you store PDFs here?
No. All processing happens locally with complete privacy.