Quick answer
To sign a PDF online, upload it to a signing tool, draw, type or upload your signature, place it on the signature line and download the signed file. A simple electronic signature like this is valid for many everyday documents in the US and EU. Some documents require a certificate-based digital or qualified signature instead.
Signing a PDF used to mean printing it, signing with a pen, scanning it and emailing it back. Today you can do the same thing in a minute from a browser or a phone. But "sign online" covers two quite different technologies, and the difference matters when a document is important.
This guide explains the two types of signature, what the law says in broad terms in the US and the EU, when a simple drawn signature is enough, and how to sign a PDF safely.
Two kinds of "signing a PDF"
People use "electronic signature" and "digital signature" interchangeably, but they are not the same thing.
Simple electronic signatures
An electronic signature is any electronic mark that shows you intend to sign: a signature drawn with your finger, your name typed in a handwriting-style font, an image of your handwritten signature, or even clicking an "I agree" button. On a PDF, it usually appears as your signature placed on the signature line, just like ink on paper.
What makes it a signature is your intent and the context: who sent you the document, how you returned it, and any record showing you agreed. The mark itself doesn't prove identity on its own.
Certificate-based digital signatures
A digital signature is a cryptographic technology. The signing software calculates a fingerprint (hash) of the document and encrypts it with the signer's private key, which is tied to a digital certificate issued by a certificate authority. Anyone can then check two things: that the signature belongs to the certificate holder, and that the document hasn't changed since it was signed. PDF readers show this as a signature panel that says whether the signature is valid.
| Simple electronic signature | Certificate-based digital signature | |
|---|---|---|
| What it looks like | Your drawn, typed or uploaded signature on the page | May show a visible signature too, plus a validation panel in the PDF reader |
| Proves who signed | Indirectly, through context (email, records, audit trail) | Through a certificate linked to a verified identity |
| Detects changes after signing | No | Yes; any later change is flagged |
| What you need | A signing tool | A certificate from a provider, often after identity verification |
| Typical uses | Everyday agreements, forms, consents, invoices, HR paperwork | Regulated industries, government filings, contracts that require it |
| Effort | Seconds | Setup once; then quick |
What the law says, in general terms
United States: ESIGN and UETA
Two laws set the ground rules. The federal ESIGN Act (2000) says a signature or contract can't be denied legal effect just because it's in electronic form. The Uniform Electronic Transactions Act (UETA), adopted by nearly every state, says much the same at the state level. Neither requires a particular technology; a typed name or drawn signature can qualify, as long as the person intended to sign and the parties agreed to do business electronically.
Both laws have exceptions. Wills, codicils and testamentary trusts, many family-law matters such as adoption and divorce, court orders and documents, and certain official notices generally still follow their own rules. Some industries also have extra requirements.
European Union: eIDAS and its three levels
In the EU, the eIDAS Regulation defines three levels of electronic signature:
- Simple electronic signature (SES): any electronic data used to sign, such as a drawn or typed signature. It can't be refused as evidence in court just because it's electronic, but its weight depends on the circumstances.
- Advanced electronic signature (AdES): uniquely linked to and capable of identifying the signer, created with means under the signer's sole control, and linked to the document so that later changes are detectable. In practice, this means a certificate-based signature.
- Qualified electronic signature (QES): an advanced signature created with a qualified signature creation device and based on a qualified certificate from a trust service provider. A QES has the same legal effect as a handwritten signature and must be recognized in every EU member state.
Most everyday documents only need a simple signature. Specific laws, or the other party, may require an advanced or qualified one for certain transactions.
When a drawn signature is enough
For a large share of everyday paperwork, a simple electronic signature is what everyone uses: a signed rental application, a consent form for a school trip, an internal expense approval, a freelance agreement sent by the client, an HR form, a delivery confirmation.
A drawn or typed signature is generally a good fit when:
- The other party sent you the document and asked you to sign and return it.
- There is a clear record of the exchange, like an email thread.
- The document is not in one of the excluded categories (wills, court documents, certain notices).
- No law or contract in your industry requires a certificate-based or qualified signature.
When the other side explicitly asks for a digital signature with a certificate, or a qualified signature, a drawn signature isn't a substitute. Use a certificate provider or trust service instead.
Step by step: sign a PDF with MyPDFDone
MyPDFDone's Sign PDF adds a simple electronic signature to your document. You can draw it, type it, or upload a photo of your handwritten signature; the background of an uploaded photo is removed so it sits cleanly on the page.
- 01Read the whole document firstCheck names, dates, amounts and every page before you sign. Signing online is quick, which makes it easy to skip this step.
- 02Upload the PDF to Sign PDFOpen MyPDFDone's Sign PDF tool and drop your file on the upload box. The document opens in the editor.
- 03Fill in any blanksAdd the date, your printed name, initials or checkmarks where the document asks for them, using the Text, Date and Check tools.
- 04Create your signatureChoose Sign, then draw your signature with a mouse, trackpad or finger, type your name in a handwriting-style font, or upload a photo of your signature.
- 05Place and size itDrag the signature onto the signature line and use the corner handle to resize it so it fits the space naturally.
- 06Preview and downloadPress Done, check the free preview of every page, then download the signed PDF for $4.99, paid once.
Signing and previewing are free. You pay $4.99 only to download the signed file, once, with no subscription. The signature is placed into the page itself, so it looks the same in every PDF reader.
Fill in forms before you sign
Many documents that need a signature are also forms: an application, a tax form, an onboarding packet. Fill them in first, and sign last.
- Interactive forms have fields you can click and type into. MyPDFDone's Fill PDF form finds them automatically; tap a highlighted field to fill it in, tick checkboxes and choose options.
- Flat forms are just printed lines with no fields. You can still type on them: use the Text tool to place text on each line and the Check tool for boxes.
- Add the date and your printed name where the document asks for them. The Date tool inserts today's date in one tap.
Signing last is a good habit for any signature, and essential for certificate-based ones: a digital signature covers the document as it was at the moment of signing, and anything added afterwards is flagged as a change.
Security tips for signing online
- Read every page before signing. Check names, dates, amounts and any attachments the document refers to.
- Use a trusted service. Check how it handles files. MyPDFDone transfers files over HTTPS, keeps them private and deletes them automatically 2 hours after upload.
- Don't leave your signature image lying around. If you upload a photo of your signature, store the original somewhere private and don't paste it into documents you don't intend to sign.
- Send the signed file to the right people only. A visible signature can be copied from a PDF, just as from a photocopy.
- Password-protect sensitive documents. If the signed file contains personal or financial details, add a password to open it with Protect PDF and share the password through a different channel, such as a text message.
- Keep your own copy. Save the signed PDF and the email or message you sent it with. That record is part of the evidence that you signed.
- Use a certificate-based signature when changes must be provable. If you or the other party need to show that nobody altered the document after signing, a simple signature is not the right tool.
If the signed file is too big to attach, see how to reduce PDF file size for email. And if you need to change the wording of a document before signing it, converting the PDF to Word may be the easier route.
Frequently asked questions
In the US, the ESIGN Act and state laws based on UETA give electronic signatures the same legal effect as handwritten ones for most transactions. EU law (eIDAS) says an electronic signature can't be rejected as evidence just because it's electronic. There are exceptions, such as wills and certain court and family-law documents. This is general information, not legal advice.
An electronic signature is any electronic sign of intent to sign, such as a drawn or typed name. A digital signature is a specific technology: it uses a certificate and cryptography to prove who signed and to detect any change made to the document after signing.
A visible signature image can be copied, just like a signature on a paper photocopy. That is why it matters who you send signed documents to, and why important agreements often use a signing process that records identity and timestamps, or a certificate-based signature.
Before. Fill in every field, date and checkbox first, check the whole document, and add your signature last. With certificate-based digital signatures this matters even more, because changes made after signing are flagged or invalidate the signature.
No. MyPDFDone's Sign PDF adds a visual electronic signature (drawn, typed or uploaded) to the page. If a document requires a digital signature with a certificate, or a qualified signature in the EU, use a certificate provider or a trust service that issues them.
Keep your own copy of the signed file, send it only to the intended people, and add a password to open it if it contains personal information. For documents where tampering must be provable, a certificate-based digital signature is the right tool, since any later change becomes visible.