How to Add a Signature to a PDF Free Online

Three ways to sign a PDF

There are three common approaches to signing a PDF digitally. First, drawing your signature with a mouse or touchscreen and embedding it as an image. Second, uploading a photo or scan of your handwritten signature. Third, using a cryptographic digital signature that verifies your identity with a certificate. For most everyday purposes — signing a contract, approving a document, filling in a form — the drawn or image signature is sufficient and what most recipients expect.

How to sign a PDF free — step by step

PDFSpot's digital signature tool lets you draw, type, or upload your signature and place it anywhere on the document.

1. 1Upload the PDF you need to sign.
2. 2The tool displays each page — navigate to the signature line.
3. 3Choose to draw your signature with your mouse or finger, type your name in a signature font, or upload an image of your existing signature.
4. 4Position the signature by dragging it to the correct location on the page.
5. 5Resize it to fit the signature field.
6. 6Click Apply and download the signed PDF.

Is a drawn digital signature legally valid?

In most countries, a drawn digital signature on a PDF is legally valid for everyday business documents — contracts, agreements, approvals, and letters. The key legal requirement in most jurisdictions is that the signature represents your intent to sign and that you are the person who signed it. For high-value legal documents, property transactions, or notarised documents, a cryptographic digital certificate signature may be required. When in doubt, check the specific requirements of your contract or consult a legal professional.

Tips for a professional-looking signature

If you are drawing your signature on a touchscreen or with a tablet stylus, it will look closest to a natural handwritten signature. With a mouse, draw slowly and deliberately — quick mouse movements produce jagged lines. Alternatively, upload a scan of your handwritten signature on white paper — crop it tightly and save it as a PNG with a transparent background for the cleanest result. Many people settle on a typed signature using a script font, which looks clean and consistent across all documents.

Signing on mobile

Signing a PDF on a phone is particularly convenient using a touchscreen. The tool works in any mobile browser — Safari on iPhone, Chrome on Android. Upload the PDF from your Files app or cloud storage, draw your signature with your finger directly on the screen, position it, and download the signed file. The whole process takes under a minute.