A signature image is reusable identity material. Uploading it to an unknown service creates a second privacy risk beyond the document itself.
Use local placement
In WatermarkPDF, the signature image is decoded and embedded by your browser. You can remove a light background, drag the image, resize it, and rotate it before export.
Storage is opt-in
New signature and stamp images are session-only by default. Select “Remember on this device” only on a private computer. The saved copy stays in that browser's IndexedDB and can be removed with “Clear all saved data.”
Good practice: keep a cropped transparent PNG, verify the final placement, and do not save signatures on shared machines.