Electronic signatures explained: types, legal value and uses
An electronic signature lets you approve a document remotely, with no printing or scanning. But not all signatures are equal: depending on the stakes, a simple visual signature may be enough, or a qualified signature from a certified provider may be required. This guide takes a factual look at the main types of signatures and what they cover.
What is an electronic signature?
An electronic signature is a set of data that expresses a person's consent to a digital document. Contrary to what many assume, it is not necessarily an image: it is above all a process that links an intention (to approve, to commit) to a specific piece of content, at a given moment.
It should be distinguished from a scanned handwritten signature. Pasting an image of a signature into a PDF reproduces a visual, but offers no technical guarantee about the signer's identity or about the integrity of the document afterwards. A true electronic signature aims, to varying degrees, to bind the signer to the file and to detect any later modification.
It is also worth separating the electronic signature, a broad legal concept, from the "digital signature" in the cryptographic sense: the latter is a technique (based on certificates and keys) often used to implement the highest signature levels. Every digital signature is electronic, but not every electronic signature relies on this cryptography.
Signature levels: the eIDAS framework and the ESIGN/UETA context
In the European Union, the eIDAS regulation distinguishes three levels. The "simple" electronic signature covers the most basic forms, such as a checked box or a mark drawn online. The "advanced" signature adds requirements: it is uniquely linked to the signer, allows them to be identified, and detects any change to the signed data. The "qualified" signature is an advanced signature relying on a qualified certificate and a secure creation device; in the EU it generally benefits from a presumption of equivalence with a handwritten signature.
In the United States, the framework rests instead on the ESIGN Act (federal) and UETA (adopted by most states). The spirit is different: in many cases these laws provide that a signature or contract cannot be denied legal effect solely because it is in electronic form, as long as there is intent to sign and consent to do business electronically. They do not impose a three-tier technical hierarchy as eIDAS does.
These frameworks coexist with many other national regulations around the world. The exact effect of a signature therefore depends on the country, the type of act and sometimes the sector: it is wise to check the rules that apply to your situation rather than assume universal equivalence.
When is a simple signature enough, and when is a qualified one needed?
For many everyday uses — validating an internal quote, approving a memo, acknowledging receipt, signing a low-stakes agreement — a simple electronic signature or a visual signature placed on a PDF is generally considered sufficient and practical. What matters most is that the intent to sign and the consent of the parties are clear.
For high-stakes acts, however, an advanced or qualified signature issued by a certified trust service provider is often recommended, or even required. This frequently applies to certain important contracts, notarized deeds, documents subject to strict regulatory requirements or high amounts, where proof of identity and integrity must be especially strong.
Because these requirements vary by jurisdiction and by the nature of the act, treat these pointers as general guidance rather than an absolute rule. When in doubt about a sensitive document, check local obligations or seek legal advice: this guide is not a substitute for professional counsel.
Best practices for signing a document
Fill in all fields and review the content before signing. A signature placed on an incomplete form, or before proofreading, can create ambiguity; on a document that needs changes, prepare the text with the edit tool first, then sign the final version.
Always keep a copy of the signed document, ideally for each party, along with the associated evidence (timestamp, exchanged emails, any certificate). This makes tracking easier and helps demonstrate consent should a dispute arise.
Finally, protect the finalized file. For a confidential document, the protect tool lets you add a password and limit access, while archiving a non-editable version helps preserve the integrity of what was signed. Avoid needlessly reopening and re-saving a signed PDF, which could weaken some advanced signatures.
How to add a signature to a PDF?
The simplest route is to use a dedicated tool such as the sign tool on pdfOutils. Upload your PDF, draw or drop your signature, position it where you want on the page, then download the signed document. This approach is perfect for visual signatures and the everyday uses described above.
If your situation calls for an advanced or qualified signature, turn to a certified trust service provider, which issues a certificate tied to your identity and applies a signature recognized by the applicable framework. Choose the level suited to the real stakes of your document, without over- or under-estimating your needs.
Frequently asked questions
Is an electronic signature legally valid?
In many cases, yes: frameworks such as eIDAS in the EU or ESIGN and UETA in the United States generally recognize the validity of electronic signatures where there is intent to sign and consent. The exact value depends, however, on the signature level, the type of act and the country; check the rules that apply to your situation.
What is the difference between an electronic and a digital signature?
An electronic signature is a broad legal concept covering any data expressing consent to a document. A digital signature is a cryptographic technique (certificates and keys) often used to produce advanced or qualified signatures. Every digital signature is electronic, but the reverse is not always true.
Is a scanned signature enough?
For low-stakes uses, a signature image placed on a PDF may be sufficient in many cases. It offers no technical guarantee about the signer's identity or the document's integrity, however. For important acts, an advanced or qualified signature is generally preferable.
What is a qualified signature?
It is the highest level under eIDAS: an advanced signature relying on a qualified certificate and a secure creation device, issued by a certified trust service provider. In the EU it generally benefits from a presumption of equivalence with a handwritten signature.