What kind of signature this is
This tool makes a visual electronic signature: an image of your handwriting, or your name in a handwriting font, placed on the page. It is the on-screen version of signing a printout and scanning it back. It is what most leases, permission slips, offer letters, invoices and HR forms need.
It is not a certificate-based digital signature. Those use a cryptographic key issued to you, record who signed and when, and make PDF readers warn if anything changes after signing. Nothing here does that: the downloaded PDF can still be edited, and there is no audit trail. When a court, bank, notary or government portal asks for a digital signature, use the service it specifies.
| This tool | Certificate digital signature | |
|---|---|---|
| What is added to the PDF | An image or text on the page | An encrypted signature over the file's bytes |
| Proves who signed | No, only that someone placed it | Yes, through the certificate issuer |
| Shows later changes | No | Yes, the reader flags the signature as broken |
| Needs an account or certificate | No | Yes |
How it works
The PDF is shown one page at a time by Mozilla's pdf.js. Your drawn strokes are captured with signature_pad, which smooths them into curves and varies the line width with speed, like a real pen. Typed names are set in Homemade Apple, a handwriting font. A photo has every pixel brighter than the paper-removal setting made transparent, with a soft edge so pen strokes stay smooth, and the ink is repainted in black or blue.
Whichever way you make it, the signature is trimmed to the ink and saved as a transparent PNG, so it sits on the signature line without a white box around it. When you save, pdf-lib draws the image and any dates or text into the page itself. The rest of the document, including its text, links and form fields, is left as it was.
Getting a clean result
- Drawing with a mouse is hard. A finger on a phone or a stylus on a tablet gives a much more natural signature, and the tool works the same on both.
- Photographing your signature: use a black or dark blue pen on plain white paper, sign larger than usual, and shoot straight down in daylight without your shadow on the page. Crop the photo close to the signature first if your phone allows it.
- Size: a typical signature line is 2 to 3 inches long. Medium fits most forms; choose Small for tight boxes such as initials fields on a contract.
- Dates are today's date from your device's clock, in the format you pick, set in Helvetica at 12 point. Double-click a placed date to change it.
Your file stays on your device
The page downloads its code once. After that, opening the PDF, making the signature, and saving the signed copy all happen inside this tab, with no upload and no account. Nothing is stored after you close the tab. You can check this by loading the page, turning off Wi-Fi, and signing a document.
Questions people ask
Is a signature made here legally binding?
For most everyday US paperwork, it can be. The federal ESIGN Act (2000) and the Uniform Electronic Transactions Act, adopted in nearly every state (New York has its own similar law), say a signature cannot be refused legal effect just because it is electronic. What matters is that you meant to sign and the other side agreed to deal electronically. There are exceptions, including wills and testamentary trusts, adoption and divorce papers, court orders, and some notices such as foreclosure, eviction and utility shut-off. The person you send it to can also insist on ink or a particular e-signing service. This is general information, not legal advice.
Is this a digital signature with a certificate?
No. This tool places a picture of your signature on the page, like signing a printout and scanning it. A certificate-based digital signature is different: it uses a cryptographic key tied to your identity, and PDF readers show a warning if anything in the file changes after signing. This tool does not do that, so the signed PDF can still be edited afterwards. If a bank, court or government office asks for a "digital signature" or "certificate", use the service they name.
Is my signature saved or uploaded anywhere?
No. The signature is drawn, typed or cleaned up inside this browser tab and is never sent to a server or stored in your browser. Close the tab and it is gone. It is, however, inside the PDF you download, as an image, so anyone who receives that PDF could copy it, the same as with a scanned signature.
Can I sign without a mouse or touchscreen?
Yes. Choose Type, enter your name, and it is set in a handwriting-style font. Press Place signature: it appears selected in the middle of the page you are viewing, and the arrow keys move it 1 point at a time (Shift plus an arrow moves 10). Pick the size in the Size list before placing, since resizing by keyboard is not available.
How do I sign several pages?
Make your signature once. Go to each page with Next or the page number box and press Place signature again; the same signature is reused every time. Duplicate copies a selected item on the same page, which helps for forms with several signature lines.
Why does it say my PDF cannot be changed?
The file is encrypted: either it needs a password to open, or it opens freely but is locked against editing, which is common with bank statements and forms from e-signing services. This tool cannot write into those. If you are allowed to sign it, open it, choose Print and then "Save as PDF" (or "Microsoft Print to PDF") to make an unlocked copy, and sign that.