Most people who say "digitally signed" mean "I drew my name on it". Those are different objects, and only one of them can be verified.
Electronic versus digital: the distinction that matters
These get used interchangeably and they are not interchangeable.
An electronic signature is any mark indicating intent to agree — a drawn squiggle, a typed name, a tick in a box, even a reply saying "I agree". It is placed onto the page as an image or as text. Nothing about the file proves who put it there.
A digital signature is a cryptographic operation using a private key. It produces a hash of the document sealed with that key, so anyone can verify two things: which certificate signed it, and that not one byte has changed since. It is a mathematical guarantee rather than a picture of one.
| Electronic | Digital | |
|---|---|---|
| What it is | A mark on the page | A cryptographic seal |
| Proves identity | No | Yes, to the certificate holder |
| Detects tampering | No | Yes, any change invalidates it |
| Needs a certificate | No | Yes |
| Legally binding | Usually yes | Yes, and stronger |
| Typical use | Contracts, forms, NDAs | Regulated filings, high value |
For the overwhelming majority of documents — a lease, an NDA, a freelance contract, a school form — an electronic signature is what is being asked for and what everyone else is using.
Are electronic signatures legally binding?
In most of the world, yes, and this is better settled than people assume.
The United States has the ESIGN Act (2000) and UETA, adopted in nearly every state, which give electronic signatures the same legal effect as ink. The European Union has eIDAS, which recognises three tiers — simple, advanced and qualified — with a qualified electronic signature carrying the same legal weight as handwriting. The United Kingdom retains its own eIDAS-derived regime plus long-standing common law that a signature is whatever the signer intended as one.
The exceptions are narrow and worth knowing: wills and codicils, some property transfers, certain court filings, powers of attorney in some jurisdictions, and documents requiring notarisation or a witness physically present. If your document is on that list, an electronic signature is not enough regardless of how it was made.
Making a signature that does not look terrible
A signature drawn with a mouse looks like a signature drawn with a mouse, and on a document that will be read by a client that matters more than it should.
- Draw on a touchscreen or trackpad, not a mouse. A finger on a phone produces a far more natural line than any mouse gesture.
- Sign larger than you need, then let the tool scale it down. Detail scales down well; it does not scale up.
- Or photograph a real signature. Sign a white sheet in black ink, photograph it in daylight, and remove the background with the Background Remover so it drops onto the page cleanly rather than as a grey rectangle.
- Keep it transparent. A signature saved as JPEG carries a white box that will sit visibly over the line it is meant to be on. PNG only.
The Sign PDF tool keeps the drawn signature on your device, which matters here more than almost anywhere else on the site: a signature image is a reusable credential, and uploading one to a service you have not audited hands over something you cannot revoke.
Order of operations
Signing goes last. This is the single most common workflow mistake and it is entirely avoidable.
A digital signature covers the exact bytes of the file. Anything done afterwards — compressing, merging, rotating a page, adding a watermark, even re-saving in some editors — invalidates it. The document then shows as "signature invalid", which looks considerably worse than an unsigned document.
So: assemble, compress, watermark, then sign. Even for a drawn electronic signature the same order is worth keeping, because compressing after signing re-encodes the signature image and can leave it visibly soft.
When you need more than a drawn mark
A drawn signature proves nothing about who drew it. For most agreements that is fine, because the surrounding context — the email thread, the parties, the conduct — establishes intent. For some it is not.
Reach for a proper digital signature, or a dedicated e-signature service with an audit trail, when:
- The amount at stake is large enough to litigate over. An audit trail showing IP, timestamp and email verification is worth having.
- A regulator specifies it. Financial filings, medical consent and government submissions often name a signature standard.
- The counterparty is unknown to you. Identity verification is the thing a drawn mark cannot provide.
- The document must be provably unaltered. Only a cryptographic signature demonstrates that.
Everything else — and it is most things — is served by a clean drawn signature on a document that was not modified afterwards.
Frequently asked questions
Is a drawn signature on a PDF legally binding?
In most cases yes. The US ESIGN Act, EU eIDAS and UK law all give electronic signatures legal effect. Narrow exceptions exist — wills, some property transfers, documents needing notarisation or a physical witness — where an electronic signature is not sufficient regardless of how it was made.
What is the difference between electronic and digital signatures?
An electronic signature is a mark on the page indicating agreement. A digital signature is a cryptographic seal that proves which certificate signed and that nothing has changed since. Most contracts need the first; regulated filings and high-value documents need the second.
Why does my signature show as invalid?
Because the file changed after signing. A digital signature covers the exact bytes, so compressing, merging, rotating or re-saving all invalidate it. Always sign last — after assembly, compression and any watermarking.
How do I make my signature look natural?
Draw on a touchscreen or trackpad rather than a mouse, and sign larger than needed so the tool scales it down. Better still, sign paper in black ink, photograph it in daylight and remove the background — that gives a real line with real pressure variation.
Should the signature image be PNG or JPG?
PNG, always. JPEG has no transparency, so the signature arrives inside a white rectangle that sits visibly over the signature line. PNG keeps the background transparent so only the ink lands on the page.
Is it safe to sign a PDF online?
It depends whether the tool uploads. A signature image is a reusable credential you cannot revoke, and a signed contract is usually confidential. A browser-based signer keeps both on your device. Check the Network tab in developer tools before using any tool for this.