Sign PDF

Why signing tools usually want an account

Searching for a way to sign a PDF turns up a wall of services that require an email address, cap you at three documents a month, stamp a watermark across the page, or park the document on their servers until you upgrade. The reason is not technical difficulty — placing an image on a page is simple — it is that a signed document is a strong sales signal. Someone signing a lease or an offer letter is a motivated user, and that moment is worth harvesting.

The documents involved make this uncomfortable. Employment contracts, tenancy agreements, consent forms, financial paperwork, medical releases: the whole category is sensitive, and handing a copy to a third party in order to add a squiggle to it is a poor trade.

This tool does the work in the page. Your PDF is read into memory, the signature is embedded with pdf-lib, and the result is handed back as a download. There is no upload, no account, no document limit and no watermark, because none of the costs that justify those exist here.

Drawn or typed — which to use

Drawing produces the closest match to a wet signature and is what most people want. A trackpad gives a wobblier line than a mouse, and a touchscreen with a finger or stylus gives the best result by a wide margin. If the first attempt looks wrong, clear the pad and try again — most people need two or three goes.

Typing generates a signature from your name in a script typeface. It looks tidier and is far quicker, and for a great many everyday documents it is perfectly acceptable. It is obviously not a reproduction of your handwriting, so for anything where a recipient will compare it against a signature they hold on file, draw it instead.

The ink colour is worth a moment's thought. Dark blue is the traditional choice precisely because it distinguishes an original signature from a photocopy, and some institutions still look for it. Black is the safer default when the document will be printed and scanned.

What kind of signature this is

This produces a visible electronic signature: an image of your mark placed onto the page. In most jurisdictions — under the ESIGN Act in the United States, eIDAS in the European Union, and comparable legislation elsewhere — an electronic signature of this kind is legally valid for the great majority of everyday agreements, and carries the same standing as signing a printout and scanning it back in.

It is not a cryptographic digital signature. That is a different mechanism: it binds a certificate issued by a trusted authority to the document, so any later alteration can be detected and the signer's identity is verifiable. If a counterparty has asked specifically for a digitally signed or certified PDF, they mean that, and you will need a certificate from a qualified provider.

Certain categories of document are excluded from electronic signature almost everywhere — wills and codicils, some property transfers, certain court filings, and adoption or divorce papers in some jurisdictions. If the document is one of those, check the requirements before relying on any electronic method.

Practical notes on placement

The page preview is rendered from your actual document, so what you see is where the signature will land. Click to place it and click again to move it — nothing is committed until you press Sign.

Size matters more than people expect. A signature around 150 to 200 points wide sits naturally on a signature line; much larger and it looks like a stamp, much smaller and it can be hard to read once printed. Use the width slider and judge it against the surrounding text in the preview.

If a document needs signing in several places, sign it once, download the result, and feed that file back in for the next signature. Each pass adds to the previous one, so a three-signature document takes three quick rounds.

One caution: a PDF with existing form fields or an existing digital signature will have that signature invalidated by any modification, including this one. That is by design — a digital signature attests to a specific set of bytes, and adding to the page changes them.