How to add a signature to a PDF, five ways, ranked by what you get back

Drop your document here and sign it now. PDF, Word and Excel all work: a .docx or .xlsx is laid out in your browser exactly as it was written, so there is nothing to convert first. Add a signature, a date, a company stamp or a watermark, then download it sealed. Free to start, no account, and the file is never uploaded to do it.

There are about five realistic ways to add a signature to a PDF and every guide on the internet describes the clicks. The clicks are not the hard part. The hard part is that four of the five produce a file that looks identical on your screen and behaves completely differently on somebody else's, and you find out which one you made at the worst possible moment, when a bank, a landlord or a client sends it back. So here they are ranked by the file they produce rather than by how easy they are, with the ten second test that tells you which kind you are holding.

First, the test that decides everything

Take any signed PDF and open it in something that is not the program that made it. A different browser will do. Now try to click the signature and drag it. If it moves, or a box appears around it, your signature is an annotation sitting on top of the page rather than part of the page, and the next person to open that file may see it in a different place, or not at all.

Everything below is really one question asked five ways: how to sign a PDF electronically, how to digitally sign a PDF, how to add an electronic signature to a PDF, or just how to get your name onto the page. That single behaviour is the difference between a document that gets accepted and one that comes back. It is also invisible in every screenshot, which is why it survives in so many how-to guides. Flattened means the mark is drawn into the page and cannot be moved, deleted or hidden. Ask for flattened, check for flattened, and most of the rest of this article stops mattering.

1. In the browser, flattened, with proof attached

The method we build, so treat the recommendation with the appropriate suspicion and then run the test above on the result. Drop the file into the panel at the top of this page. Draw the signature with a finger or a trackpad, or type it and pick a style, then place it where the line is and download.

What comes out is flattened, so the signature is part of the page. It carries a certificate naming the signer and the time, and a public verification page the recipient can open without an account. Word files come back as Word rather than as a PDF you did not ask for. It costs $1.50 for the completed download, nothing to try, and no account to start.

This is the right method when somebody else has to accept the document: a lender, a landlord, a regulator, a client's finance team. What you are buying is not the signature, which anybody can draw. It is the thing that answers "how do I know this is genuine" without a phone call.

2. Adobe Acrobat Reader, free, on a computer

Open the PDF in the free Acrobat Reader, choose the Sign icon or Fill and Sign, then Add Signature, and draw, type or upload an image of your name. Click where you want it and it lands there. This is free, it is what most people mean by an electronic signature PDF, and it is fine for low stakes documents.

Two catches worth knowing before you rely on it. By default the mark is an annotation, so run the drag test: use Save As and choose to flatten, or print to PDF, if you want it fixed. And Acrobat's free tier stops at the signature. The moment you want to edit the underlying page, convert the file or add a certificate based digital signature to the PDF, you are in Acrobat Pro at around $20 a month.

3. Preview on a Mac, or Markup on an iPhone

Preview will capture your signature from the trackpad or by holding a piece of paper up to the camera, then let you drop it onto any page. On an iPhone or iPad, open the attachment, tap the Markup pen, then the plus, then Signature. Both are genuinely quick and both are free, and for a school form or a delivery note they are the correct answer.

What you do not get is any record. There is no timestamp, no certificate, nothing tying the mark to a person, and the signature image is now saved on that device for anyone who picks it up. For anything where the other side might one day ask who signed, this is a picture of a signature rather than evidence of one.

4. Print, sign, scan

Still the most common method in the world and still the worst. It costs paper and twenty minutes, the scan comes back skewed and grey, the file is four times the size, and it destroys any text layer the document had, so nobody can search it afterwards.

It also proves nothing that the alternatives do not. A scanned signature is an image of ink, and an image can be lifted out of one document and dropped into another by anybody with a free editor. If your reason for printing is that a scanned signature feels more official, it is the one method that makes forgery easier rather than harder.

5. A certificate based digital signature

The heavyweight option. You obtain a certificate from a trust provider, and Acrobat or a similar tool uses it to add a digital signature to the PDF that is cryptographically bound to the file. Change one byte afterwards and the signature reports as invalid. This is what eIDAS calls an advanced or qualified electronic signature, and it is what some governments and some regulated processes require.

It is also a real project: identity vetting, a certificate that expires, a token or a cloud signing service, and a counterparty whose software has to be able to check it. Do this when a rule tells you to. For ordinary commercial documents it is heavier than the situation needs, and a flattened signature with a verifiable audit certificate satisfies almost everybody who asks.

Where to put it on the page

On the signature line, not near it. If the document has a printed line with a name under it, the mark sits on the line and the printed name stays visible. Overlapping the typed name is the most common way to make a document look wrong.

Sign every page that has a signature block, not just the last one. If the document has initials boxes, put initials in them, because a document returned with three of five boxes filled comes back.

And date it in the format the document uses. A UK contract dated in US order is the small error that starts an argument later.

The three minute version

Low stakes and you are on a Mac or a phone: use Preview or Markup. Free, immediate, no account.

Ordinary business document on a computer: Acrobat Reader, then flatten it before sending.

Anything somebody else has to accept, or anything you might need to prove later: drop it into the panel at the top of this page, place a signature on the PDF, and download a flattened file with a verification link attached. One minute, $1.50, and nobody has to take your word for it.

Questions people ask about this

How do I add a signature to a PDF for free?

On a Mac, open it in Preview and use the signature tool. On an iPhone, open the attachment and use Markup. On Windows, Adobe Acrobat Reader's Fill and Sign is free. All three put a mark on the page for nothing, and none of them produce a record of who signed or when, so keep them for low stakes documents.

How do I insert a signature in a PDF that has no signature field?

You do not need a field. Every method here places a signature anywhere you click, whether the PDF was made fillable or not. If a tool refuses, it is a form filling tool rather than a signing tool: with the PDF open, insert a signature as free placement instead.

What is the difference between an electronic signature and a digital signature in a PDF?

An electronic signature is the mark plus the record of intent around it, which is what most agreements need and what our certificate provides. A digital signature is a specific cryptographic technique that binds a certificate to the file so tampering breaks it. Which one you need is set by the rule or contract in front of you, so check the document's own requirements or ask the party who will receive it.

How do I know my signed PDF will not move or disappear?

Open it in a different program from the one that made it and try to drag the signature. If it moves, it is an annotation and it can move for the recipient too. A flattened file draws the mark into the page permanently, and everything downloaded here is flattened by default.

How to put a signature on a PDF from a phone?

iPhone Markup and Android's built in PDF tools both do it, and any browser can reach the signer on this page, so you can attach a signature to a PDF from a phone without installing anything.

Is a PDF signature legally binding?

In most countries an electronic signature is binding for ordinary commercial agreements, under laws such as the ESIGN Act and UETA in the United States and eIDAS in Europe. Wills, some property transfers and a short list of other documents are excluded, and the list differs by jurisdiction, so confirm with a qualified adviser for anything unusual. This is general information rather than legal advice.

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What PDF Verified is, and what it is not

Electronic signature law is settled in broad terms and specific in the details. The ESIGN Act, UETA, eIDAS and their equivalents recognise electronic signatures across more than 190 countries, and what decides a particular case is intent to sign plus evidence connecting the signature to the signer, which is what the audit certificate records. Certain document types carry their own formalities wherever you are: deeds, wills, some property instruments, and anything requiring a witness or a notary. Sign only what you are authorised to sign, since applying another person signature without their authority is forgery whatever tool is used.

PDF Verified is a tool for preparing, signing, stamping and checking documents. It is not a law firm, a compliance service or a forensic examiner, and nothing here is legal, financial or compliance advice. Requirements differ by country, by document type and by the party asking, so check what applies to your document before you rely on it, and take advice where the document matters. You are responsible for the documents you create, sign and send, and for having the authority to do so: signing or stamping in somebody else name, or as an organisation you do not represent, is forgery whatever tool is used. To the extent the law allows, we accept no liability for how a document made with this tool is used or relied on. The full position is in our terms of service.

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