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PDF Toolkit

Underline PDF

Underline important text in your PDF documents.

Runs in your browser Free · No sign-up

or drop a PDF here

PDF · up to 50 MB

Processed in your browser – your files never leave your device.

Edit text Add text & images Highlight Draw Shapes Sign Stamps Watermark Page numbers Rotate & reorder pages

How to use Underline PDF

  1. 1

    Upload your PDF

    Drop your PDF into the upload area or choose it from your device.

  2. 2

    Edit in your browser

    Use the toolbar to add text, images, shapes, highlights or your signature.

  3. 3

    Download

    Click "Download" to save the edited PDF.

Frequently asked questions

Is Underline PDF free?

Yes. Underline PDF is completely free. There is no registration, no subscription and no watermark on your files.

Are my files safe?

Whenever possible your file is processed directly in your browser and never leaves your device. When server processing is needed, files are deleted automatically right after processing.

Does it work on my phone?

Yes. The tool works in any modern browser on Windows, macOS, Linux, Android and iPhone – nothing to install.

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