pdfpix

Add a signature to a PDF

or drop one here
Choose a PDF first.

Draw, type or upload a visual signature, place it on the PDF page, and download only after the output is reopened and every mark is shown to be visible. The PDF and signature stay in this tab. This is not a certificate signature.

How to add a signature to a PDF

  1. Choose a PDF

    Press Choose a PDF, or drop one on the page. The file opens in this browser tab.

  2. Create the signature

    Draw with a mouse, finger or stylus, type your name, or choose a PNG or JPG signature image.

  3. Place the marks

    Put the signature, initials, date or other short text on a page. Drag a selected mark and adjust its size.

  4. Read the check, then download

    The output is reopened. Every mark must be visible and the original selectable text must remain before the download appears.

A visible signature is not a certificate signature

This tool writes the signature onto the page. It does not prove who signed, verify identity, issue a certificate, add a trusted timestamp or create an audit trail. Use a certificate-based signing service when the recipient asks for a verifiable digital signature.

What it does prove is narrower, and worth knowing. The signed copy is reopened, its page geometry and selectable text are compared with the source, and every marked page is rendered before and after so the pixels inside each mark can be checked for a visible change. If a mark did not survive, or a page lost text, the run stops with that error and there is no download to take.

Mark sizes and limits

The size control sets a mark's width from 8% to 60% of the page width, and the height follows the shape of the image, up to 45% of the page height. A signature starts at 30% of the page width, a date at 22%, and initials or text at 18%.

A typed signature or text mark holds up to 80 characters, and initials up to 12. An uploaded PNG or JPG is scaled down until its longer side is at most 1,600 pixels. A drawing with fewer than 20 visible pixels is refused with the message Add a visible signature first.

Place date writes today's date from this device's clock, in the medium style of your browser's language, such as Mar 4, 2026 in US English. To write a different date, type it into Text and use Place text.

Questions

Is this a digital signature?
It is a visual electronic signature: page content that looks like your signature. It is not a certificate signature, timestamp, identity check or tamper-evident audit trail.
Does the signature leave my device?
No. The PDF and signature stay in this browser tab. The signature is not sent to analytics, saved to local storage or kept for another visit.
Can I sign on a phone?
Yes. The drawing pad and page marks use pointer controls that accept a finger, stylus, mouse or trackpad.
Can I use a photograph of a signature?
Yes. Choose a PNG or JPG. Light-background removal can make white paper transparent while keeping darker ink. Check the page preview before you run the tool.
What happens to an existing certificate signature?
Changing any page content can invalidate it. The tool warns when the PDF contains signature fields and requires confirmation before it runs.
Does the tool keep selectable text?
Yes. It adds image marks to the existing pages. The output must retain at least 98% of the original non-space selectable characters and keep the same page geometry.
What does the signed-PDF check prove?
It reopens every page, compares page geometry and selectable text, then renders the marked pages before and after and checks for visible pixel changes inside every mark.
Is a typed signature, date or text mark selectable in the signed PDF?
No. Every mark, including a typed signature, initials, the date and other text, is drawn as a PNG image and placed on the page. Those marks cannot be searched or copied as text. The text already in the PDF stays selectable.

Related tools

Each runs in a browser tab like this one, reads its own output back before the download, and needs no account. The footer links every tool.

Where to go next