How to Create a Digital Signature (and When You Need One)

“Digital signature” is used for two very different things. Most people searching for it want a picture of their signature they can put on a PDF. Technically, that is an electronic signature. A digital signature in the strict sense is a cryptographic seal backed by a certificate. This guide explains the difference, tells you which one you actually need, and shows how to create both.

Electronic signature vs. digital signature

	Electronic signature	Digital signature
What it is	Any electronic mark showing you agree: typed name, drawn signature, signature image, “I agree” checkbox	A cryptographic signature created with a private key and a certificate
What it proves	Your intent to sign	Who signed (via the certificate) and that the file was not changed after signing
What it looks like	Your signature on the page	Often a signature image plus a certificate panel in the PDF reader (“Signed and all signatures are valid”)
How to make one	Signature generator, phone app, Markup, Preview	Acrobat, Word or a signing service, with a digital ID
Typical use	Leases, HR forms, school forms, invoices, most contracts	Government and tax filings, some legal and notarial documents, regulated industries

Every digital signature is a kind of electronic signature, but most electronic signatures are not digital signatures.

Which one do you need?

Usually an electronic signature. In the United States, the ESIGN Act (2000) and the Uniform Electronic Transactions Act (UETA), adopted by almost every state, say a signature or contract cannot be denied legal effect just because it is electronic. In the EU, the eIDAS Regulation recognises three levels: simple, advanced and qualified electronic signatures. A signature image placed on a PDF is a simple electronic signature, and it is accepted for the large majority of everyday agreements.

You need a certificate-based digital signature when:

• the recipient explicitly asks for a “digitally signed” or “certified” PDF,
• a government portal or tax authority requires it,
• an EU process requires an advanced or qualified electronic signature (a qualified one has the same legal effect as a handwritten signature across the EU),
• your industry or contract demands proof that the document was not modified after signing.

Some documents cannot be signed electronically at all, depending on where you live: wills, some family-law documents, court orders, certain real-estate deeds and documents that must be notarised in person. If in doubt, ask whoever requested the signature. This is general information, not legal advice.

How to create an electronic signature (the one most people need)

Option 1: Online, in a minute

1. Open the free signature generator.
2. Type your name and pick one of 14 cursive or handwritten fonts, or switch to Draw it and sign with your mouse or finger.
3. Choose black or blue ink.
4. Click Download PNG. You get a transparent image of your signature, ready to insert into a PDF, Word or Google Docs file.

Nothing is uploaded: the generator runs in your browser.

Option 2: On your phone, directly on the document

The Signature Maker app for iPhone and Android stores your signature (drawn, typed or scanned from paper) and places it on PDFs and photos. Create it once, open the document, tap Add Signature, position it and tap Save Document.

Option 3: With built-in tools

• iPhone and iPad: the Markup tool in Files and Mail. See how to sign a PDF on iPhone.
• Mac: Preview’s Sign tool. See how to sign a PDF on Mac.

How to create a certificate-based digital signature

You need a digital ID: a certificate and private key that identify you. There are two kinds.

• Self-signed digital ID. Free and created in seconds, for example in Adobe Acrobat. It proves the file has not been changed since signing, but nobody vouches for your identity, so recipients may see a warning that the signer’s identity is unknown.
• Certificate from a trusted provider. Issued by a certificate authority or, in the EU, a qualified trust service provider after it verifies your identity. Recipients’ software trusts it automatically. Some countries issue them on national ID cards.

In Adobe Acrobat

1. Open the PDF and choose the tool to use a certificate (in recent versions: All tools → Use a certificate → Digitally sign).
2. Drag a box where the signature should appear.
3. Choose your digital ID, or create a new self-signed one when prompted.
4. Choose how the signature looks (it can include your signature image), enter your ID password and save the signed PDF.

In Microsoft Word (Windows)

1. Go to Insert → Signature Line and fill in the signer details.
2. Right-click the signature line and choose Sign.
3. Type your name or select a signature image, then choose a certificate and click Sign. Word marks the document as final.

Menus differ between versions of Acrobat and Word; look for “certificate”, “digital ID” or “digitally sign”.

Frequently asked questions

Is a picture of my signature a digital signature?

Not in the technical sense. A picture of your signature on a PDF is an electronic signature, which is legally valid for most documents. A digital signature additionally uses a certificate to prove who signed and that the file was not altered.

Can I create a digital signature for free?

Yes. You can create an electronic signature for free with the online signature generator or a phone app. You can also create a free self-signed digital ID in Adobe Acrobat, though recipients’ software may not trust it automatically.

Is an electronic signature legally binding?

Yes, for most documents. The US ESIGN Act and UETA and the EU eIDAS Regulation give electronic signatures legal effect. Exceptions include wills and documents that must be notarised or require a qualified signature.

What is a qualified electronic signature?

It is the highest level of electronic signature under the EU eIDAS Regulation. It is created with a qualified certificate, issued after identity verification by a qualified trust service provider, using a secure signature device, and it has the same legal effect as a handwritten signature in every EU country.

How do I make a digital signature on my phone?

For an everyday electronic signature, use an app like Signature Maker: create your signature by drawing, typing or scanning it, then place it on a PDF or photo. Certificate-based digital signatures on phones generally require Adobe Acrobat or a signing service that holds your digital ID.