Is an electronic signature legally valid?

In many jurisdictions electronic signatures are recognised for most everyday agreements, but the rules vary by country and by document type. For anything with legal or financial weight, confirm what the receiving party requires.

Can I reuse the same signature later?

Not automatically, because nothing is stored. If you sign often, keep a transparent PNG of your signature and add it with the image watermark tool instead.

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

An electronic signature is a mark placed on a document. A digital signature embeds a cryptographic certificate that identifies the signer and detects any later change to the file. This tool produces the first kind.

Can the signature be removed from the document afterwards?

It is drawn into the page content rather than added as a removable annotation, so it will not be deleted by a casual click. But no image-based signature can prevent a determined edit — that is what certificate-based signing is for.

Can someone else sign the same document after me?

Yes. Send them the signed PDF and they can add their signature to it in the same way. Each pass adds one signature to the file.

Is my signature stored anywhere?

No. It exists in the browser tab while you are working and is gone when you close it. Nothing is uploaded and nothing is saved for next time.

How to sign a PDF on your phone

Published 22 July 20265 min read

The usual routine is to print the page, sign it, photograph it and send back something crooked and grey. You can skip all of that: draw your signature with a finger, place it, and download a clean signed PDF. What follows is how to do it well, and — just as importantly — when this kind of signature is the right one.

Signing it

Your signature exists only in the browser tab while you work. It is not stored, uploaded or kept for next time — which also means you draw it fresh each session. That is a deliberate trade: a stored signature is a convenience, but it is also a reusable copy of something that should not be lying around.

1Open the Sign PDF tool and choose your document.
2Draw your signature with a finger or mouse, or type your name to have it rendered in a script style.
3Choose which page it belongs on and where, and set the size.
4Press Sign and download the finished document.

What this kind of signature actually is

This places a picture of your signature onto the page, exactly as signing paper does. It is an electronic signature, and for everyday agreements — a rental form, a school letter, an internal approval, an NDA between small businesses — that is normally what is being asked for.

It is not a cryptographic digital signature. It does not embed a certificate that proves who signed and detects later tampering. Understanding the difference matters, because the words are used loosely and the legal weight is not the same.

Type	What it proves	Typical use
Electronic signature (this tool)	That a signature mark was placed on the document	Everyday agreements, internal approvals, forms
Digital signature (certificate-based)	Who signed, and that the file has not changed since	Corporate contracts, regulated filings
Qualified electronic signature	The above, with a legally recognised identity check	Government portals and processes that require it by law

If a counterparty asks for a certified, qualified or digitally certified signature, or the document is going to a court or a government portal that requires one, you need a certificate-based service — not this or any other image-based tool.

Making it look right

Draw larger than you think. A signature drawn slowly and big scales down to something clean, while one drawn tiny looks shaky when enlarged. If you are using a finger, use the whole width of the drawing area even though it feels absurd.

Keep it modest on the page — around 25 to 35% of the page width sits naturally on a signature line. A signature spanning half the page reads as a mistake.

Place it on the last page unless the form marks a specific spot. If there is a printed line, sit the signature on it rather than above or below, and leave the printed name visible underneath.

Phone or laptop?

A finger on a touchscreen produces a better signature than a mouse, by a wide margin. Drawing a smooth curve with a mouse is genuinely difficult, and it shows.

If you have a stylus or an Apple Pencil, that is the best option available — it is close to signing on paper. If you only have a laptop with a trackpad, consider typing your name in a script style instead; a clean typed signature looks more professional than a wobbly drawn one.

A useful middle route: draw the signature once on your phone, keep it as a transparent PNG, and place that image on documents from your laptop with the image watermark tool.

If you sign documents often

Redrawing your signature for every document gets old quickly. Make a reusable signature file once: sign a blank white sheet with a dark pen, photograph it in good light, and remove the background so you have a transparent PNG.

Then use the image watermark tool to place it, which gives you the same result with the same privacy properties and no redrawing. Keep that PNG somewhere sensible — it is a reusable copy of your signature, so it deserves the same care you would give a scanned ID.

Before you send it

Check the obvious things: the signature is on the right page, it is not covering any text, the date field is filled in if there is one, and the file opens correctly after downloading.

If the document is a scan and the result is heavy, compress it before sending — a signed contract does not need to be 30 MB.

And keep the unsigned original. If something needs correcting, re-signing a clean copy is far tidier than trying to undo a placed signature.

A word on where signatures travel

A signature image is worth protecting. Once someone has a clean copy of your signature, they have something that can be placed on any document at all — which is precisely why services that ask you to upload a contract in order to sign it deserve a second thought.

It is worth noting that this tool never sends the document or the signature anywhere, because both stay inside your browser. You can verify it the same way you would verify any such claim: load the page, go offline, and sign anyway.

Try it now — free and private

The tool runs entirely in your browser. Your file never leaves your device.

Sign PDF

Common questions

Tools mentioned in this guide

Watermark PDFStamp a custom text watermark over every page.Image watermarkStamp your logo or any image over every page.Compress PDFShrink file size while keeping the best possible quality.

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