"Could you sign the PDF and send it back?" Sounds simple, until you hear it on a day the printer is out of ink and you have never owned a scanner. The old way: print, sign, scan, send. The new way: add your signature on screen, send. That's why "how to sign a PDF" is such a popular search; everyone is looking for the second way.
But careful: "please sign" can mean two very different things. Sometimes the other side just wants your signature to appear on the page; sometimes they expect an electronic signature with the same legal weight as one in ink. This guide shows how to sign a PDF step by step, then explains the difference between visual, electronic and digital signatures in plain language. It isn't legal advice, but it helps you ask the right question.
How do I sign a PDF?
With Sign PDF, no printer or scanner needed:
- Pick the PDF.
- Create your signature: draw it with your finger or mouse, type your name (it's turned into a handwriting font), or upload a photo of a signature you made on paper.
- Drag the signature where it belongs on the page and resize it.
- Add initials, your name and the date if needed. If the initials should be on every page, use "Apply to all pages".
- Sign and download.
Signatures you save are waiting for you next time, in this browser. The signature is added in your browser; neither the document nor the image of your signature is sent to a server. Your signature isn't floating around somewhere, which is a good thing.
A note from Yeti: my signature is a paw print. Yours is probably more legible, but they're added exactly the same way.
How do I sign a PDF on my phone or iPhone?
Sign PDF works in your phone's browser too, and a finger-drawn signature looks far more natural than a mouse-drawn one. Download the PDF from email or your chat app, pick it in the tool and draw on the screen.
On an iPhone there's also a built-in route: open the PDF in Files or Mail, tap the Markup icon and add + > Signature. It's quick, but for initials, dates and multi-page documents a dedicated tool is more comfortable.
Visual, electronic and digital signatures: what's the difference?
Visual signature. A picture of your signature: drawn on screen, typed, or photographed. It's placed on the PDF as an image. Technically it doesn't prove who signed, but in many situations where both sides agree, it's accepted as a signature.
Electronic signature. A legal umbrella term. In the EU, the eIDAS Regulation defines three levels: simple, advanced and qualified. Typing your name under an email, or adding a signature image to a PDF, can count as a "simple electronic signature". Only a qualified electronic signature is equivalent to a handwritten one across the EU.
Digital signature. A technical term. A certificate and cryptographic key unique to you create a "fingerprint" of the document's contents. Your PDF reader shows whether the signature is valid and whether the document changed after signing. Qualified electronic signatures use this technology.
When do I need a certified electronic signature?
In the US, the ESIGN Act and UETA make electronic signatures valid for most transactions, with exceptions such as wills. In the EU, eIDAS applies, and in many countries (Turkey's Law 5070 is one example) only a certificate-based "secure" or qualified signature carries the same weight as ink. Such signatures are issued by an accredited certificate provider, usually on a USB token, a smart card or a mobile signature, and applied with the provider's signing software.
Filing documents with a court, bidding in public tenders and some official applications typically require that level. A visual signature doesn't replace it.
When is a visual signature enough?
For most everyday paperwork:
- Internal approvals, leave forms, expense claims
- Quotes and business letters where the other side accepts a scanned signature
- Delivery notes, sign-up forms, school and club documents
- Documents between a tenant and landlord who both accept it
Not sure? Ask whoever wants the document: "Is a visual signature fine, or do you need a certified e-signature?"
Good habits after signing
- Flatten forms you filled in. Fillable fields can still be changed after signing. Flatten PDF makes them part of the page. You can fill the form first with Fill Form.
- Keep the original. Store signed and unsigned versions under different names.
- Know what encryption does. Protect PDF keeps the document away from unauthorized people, but unlike a digital signature it doesn't prove nothing changed after signing.
Frequently asked questions
Can I sign a PDF for free?
Yes. Sign PDF is free; no account, and you don't have to register your signature anywhere.
How do I sign a PDF without Adobe?
Use Sign PDF in your browser; no Adobe or other software required. Preview on a Mac and Markup on an iPhone can add a visual signature too.
Is a visual signature legally binding?
It depends. It's enough for many everyday agreements both sides accept; where a signature must carry the same legal effect as ink (courts, some official filings), you need a qualified electronic signature.
How do I add a picture of my signature to a PDF?
Sign a sheet of white paper with a dark pen, take a photo, and add it with the upload option in Sign PDF. An evenly lit photo without shadows gives the cleanest result.
Can someone change a PDF after I have signed it?
A PDF with a visual signature can technically still be edited. If you need proof that nothing changed, use a certificate-based digital signature.
In short
| Need | The right tool |
|---|---|
| Signature visible on the page, accepted by the other side | Visual signature |
| Proof of who signed and that the document hasn't changed | Digital signature |
| The same legal effect as a handwritten signature | Qualified electronic signature |
Yeti's signature tool is for the first row, and says so clearly. It does, however, end the printer-and-scanner routine for good.