How Sign PDF Works
DocDox Sign PDF lets you add handwritten or uploaded signatures to any PDF document without installing software, creating an account, or sending your files anywhere. Every step — rendering the PDF, capturing the signature, and embedding it — happens locally in your browser using PDF.js, react-konva, and pdf-lib.
Create your signature by drawing on the signature pad with a mouse or touchscreen, or upload an existing PNG signature image. The signature appears as a draggable, resizable element overlaid on the PDF page. Position it precisely using drag-and-drop, resize it to the correct scale, and use keyboard shortcuts to manage placement (Delete to remove, Escape to deselect). Each page is handled independently, so multi-page contracts are fully supported.
At export, pdf-lib embeds your signature as a PNG image burned into the PDF at the exact position you specified. Screen coordinates are mathematically mapped to PDF coordinates, ensuring pixel-accurate placement regardless of page size or how the document was zoomed in the viewer.
Are the signatures legally binding?
This creates a visual signature image embedded in the PDF. For legal enforceability, consult your jurisdiction's e-signature laws. For formal legal documents, use a dedicated e-signature service with audit trails.
Can I sign multiple pages?
Yes. Add your signature to as many pages as needed before exporting the final document.
Is my signature image stored anywhere?
No. The signature exists only in your browser session and is cleared when you close the tab.