How to sign a PDF without printing, scanning, or faxing

Somewhere out there is a person who still prints a contract, signs it with a pen, scans it back in, and emails the result — and that person is wasting twenty minutes and a sheet of paper on something that takes thirty seconds. You can sign a PDF directly. But "sign" means two different things, and knowing which one the situation calls for keeps you from either overcomplicating a permission slip or under-securing a legal agreement.

Two kinds of "signature"

• An electronic signature. A drawn, typed, or uploaded image of your signature placed onto the page. It's visual proof of intent — the digital equivalent of signing with a pen. For the vast majority of everyday documents (forms, internal approvals, NDAs, leases), this is exactly what's expected and it's legally recognized in most places.
• A digital signature. A cryptographic certificate bound to the document that proveswho signed and that the file hasn't changed a single byte since. This is what you want for high-stakes or regulated contexts where tamper-evidence matters.

How to sign a PDF, step by step

1. Open the sign tool and load the document.
2. Create your signature: draw it with a trackpad or finger, type it in a signature font, or upload an image of your real signature on a transparent background.
3. Place it on the signature line, resize it to look natural, and add the date if needed.
4. Export. The signature is now part of the page, not a floating sticky note.

Flatten it so it can't be moved

A signature added as a movable annotation can sometimes be dragged off or deleted by the next person who opens the file. Flattening the document merges your signature permanently into the page so it behaves like ink on paper. If you're signing something that matters, flatten before you send.

Sign, then protect

A signature shows intent; it doesn't stop someone editing the rest of the page afterward. For agreements, a sensible last step is to lock the file — or, for true tamper-evidence, use a cryptographic digital signature, which invalidates itself visibly if the document is altered. The two approaches answer different questions: "can people change this?" versus "can I prove it wasn't changed?"

Requesting signatures from other people

Signing your own document is half the story; often you need someone else to sign. The clean version is to send a flattened PDF with clearly marked signature fields, so the other party draws or types their signature in the right spot and sends it back — no printing on either end. Keep the round-trip inside tools you trust, because a signature request usually means the document contains exactly the kind of detail you don't want scattered across free upload sites.

The documents you sign are the ones that matter

Contracts, offer letters, financial agreements, consent forms — signing is, almost by definition, something you do to important documents. Running those through a free "sign PDF online" site means uploading the agreement (and often your actual signature image, which is reusable) to a server you don't control. We keep signing in the same private workspace as the rest of Arthize for that reason. The full argument is in what happens when you upload a PDF to a free tool.

Signing rounds out the "security" trio in the PDF workflow guide, alongside encryption and redaction.