Sign a PDF document without printing an scanning

Put a signature in a pdf file.

If you want to use a desktop app to input your signature in a pdf file, Xournal is probably the most convenient tool for signing PDFs on Linux. It can annotate PDFs, adding images to them. First, you’ll need to create an image of your signature—sign a piece of paper, scan it into your Linux system, and clean it up. You could potentially just capture a photo of it with your webcam or smartphone’s camera, too. You may want to tweak it in GIMP so it has a transparent background, or just make sure you sign a white piece of paper and that the background is entirely white.

Install Xournal from your Linux distribution’s software installation tool, open the PDF, and click the Tools > Image menu option. This will let you insert the image of your signature, and you can reposition and resize it as necessary so it fits in the signature field.

Having to actually scan and create an image file is a little bit annoying, but you can use this method to quickly sign documents in the future after you’ve gotten a good image of your signature.