How to sign a PDF

Are you signing it, or do you need someone else's signature?

These are two different jobs, and most of the confusion around signing PDFs comes from mixing them up. If a landlord has emailed you a lease and wants it back signed, you only need to put your own signature on the page. Every phone and computer can do that without paying anything.

If you are the landlord, the job is harder. You need the tenant to sign, you need to know it was really them, and you want proof later if anyone disputes it. A picture of a signature pasted onto a page proves very little on its own. That is where an e-signature service earns its fee: it verifies the signer's email, records each step, and locks the finished file so changes show.

The free ways to add your own signature

Each of these stamps an image of your signature onto the page. Pick whichever is already on your device.

• Mac: open the PDF in Preview, click the Sign button in the Markup toolbar (or Tools > Annotate > Signature), create a signature with the trackpad, camera or your iPhone, then drag it into place.
• iPhone and iPad: open the PDF in the Files app or a Mail attachment, tap the Markup button, tap the Add button (+), choose Add Signature, sign with your finger and tap Done.
• Windows: open the PDF in Microsoft Edge, click Draw in the toolbar, sign with a mouse, pen or finger, then click Save.
• Any computer: Adobe Acrobat Reader is free; open the file, choose Fill & Sign, then Sign or Add signature, and type, draw or import an image.
• Android: Adobe Acrobat Reader for Android has the same Fill & Sign tool, and the Google Drive app lets you annotate a PDF with a pen.

What a signature image does and does not prove

A drawn signature on a PDF is a valid electronic signature in most countries for ordinary contracts. The law cares that you meant to sign, not what the squiggle looks like. The weakness is evidence. If the other side later says they never signed, a PNG on page three cannot show who placed it, from which device, or whether the text above it was edited afterwards.

An e-signature service fills that gap with an audit trail: the signer's verified email, IP address, browser, the time they opened and signed, and a fingerprint of the file. For a coffee-shop supplier form, the free route is fine. For a tenancy agreement, an employment contract or a loan, collect the evidence.

Getting a PDF signed by someone else with Sign PDF

Upload the PDF (or a Word file, or a photo of a printed page) and we read the wording around each blank to place signature, initials, date and name boxes, and work out whether each one belongs to the Landlord, the Tenant, the Employee or a Witness. You check them, drag any that are off, type each signer's name and email, and send.

Signers get an email link, confirm a six-digit code sent to that address, and sign in the browser. They do not need an account or an app. When the last person signs, the boxes are written into the PDF, a certificate of completion is added at the end, and the file is sealed with a digital signature and a DigiCert timestamp. Anyone can check a copy later at signpdf.ai/verify.

Sign PDF costs $5 a month for two documents or $10 a month for unlimited, with no annual contract. You can upload a file and see the boxes placed before you sign up or pay.

Which method should you use?

If you are the one signing and the other party has not asked for anything special, use the free tool on your device. If you are collecting a signature, use a service that records evidence. And if the document is a will, a deed that must be witnessed in person, or anything that needs a notary, check the local rules first: some of those still need ink.