Choosing the right electronic signature format isn’t just a technical decision: it’s a legal and operational one. Nowadays, we can find examples of electronic signature use in all types of sectors and industries. These solutions are not exclusive to public administration; electronic signature platforms are being progressively adopted across the private sector as well.
In this article, you will discover the main electronic signature formats, different use cases in practice, and a summary of the key advantages over the traditional handwritten signature.
What is an electronic signature?
Before exploring the different electronic signature formats, it is helpful to start with a basic definition. In simple terms, an electronic signature is a system of identification and consent that replaces handwritten signatures in the digital realm.
In the legal environment, we find a specific definition in the European Union Regulation No. 910/2014, eIDAS, which establishes a common regulatory framework for electronic signature formats across the EU.
According to this regulation, we refer to an electronic signature when “electronic data is attached to other electronic data or logically associated with them, used by the signatory to create a signature.”
Therefore, an electronic signature (at least in some of its forms):
- Unequivocally identifies the signatory.
- Guarantees the integrity of the document, ensuring it has not been modified or altered after signing.
- Ensures non-repudiation, since it is reliable proof of the consent granted by the signatory, who cannot deny having signed the document in question.
The main electronic signature formats
Electronic signatures can be implemented in several different formats, each with its own characteristics, security level, and legal standing. Understanding which format applies to your situation is essential for both compliance and operational efficiency.
Under the eIDAS framework, there are three legally recognized electronic signature formats:
1. Simple electronic signature (SES)
The simple electronic signature format has the lowest level of security. It consists of a basic association of electronic data, such as logging in with a username and password, clicking an “I accept” checkbox, or scanning a hand-signed paper document and sending it by email.
This format is appropriate for low-risk transactions where strong signer identification is not required; for example, internal approvals or newsletter opt-ins.
2. Advanced electronic signature (AES)
The advanced electronic signature offers a significantly higher security level. This electronic signature format:
- Allows for the unequivocal identification of the signatory.
- Is uniquely linked to the signatory.
- Allows the signatory to retain control.
- Is linked to the signed document in such a way that any subsequent modification is detectable.
The advanced electronic signature format is the most widely used by businesses for contracts, HR documents, NDAs, and commercial agreements, thanks to its strong legal standing combined with ease of use.
3. Qualified electronic signature (QES)
The qualified electronic signature is the highest-security electronic signature format recognized under eIDAS. It is an advanced electronic signature with two additional requirements:
- It has been generated by a qualified electronic signature creation device.
- It is based on a qualified electronic signature certificate issued by a Qualified Trust Service Provider (QTSP).
In the EU, the qualified electronic signature format carries the same legal value as a handwritten signature, and is the preferred format for regulated industries, high-value contracts, and cross-border transactions. As Europe’s largest QTSP, Signaturit Group, a Namirial Company issues qualified electronic signatures that are recognized across all EU member states.
>> Related post: Digital signature vs. electronic signature — what’s the difference?
Other common electronic signature formats by implementation method
Beyond the three eIDAS tiers, electronic signatures can also be categorized by how they are technically implemented:
- Digital certificates issued by a certificate authority — used in advanced and qualified formats to cryptographically bind the signer’s identity to the document.
- Biometric signatures — identification and signing using biometric data (pressure, tilt, speed) captured on a calibrated tablet device. This format is common in face-to-face environments such as banking branches or point-of-sale scenarios.
- OTP (one-time password) authentication — a username/password or SMS-based code is used to verify the signer’s identity before signing, typically used in advanced signature workflows.
- Digitized handwritten signatures — a scanned image of a physical signature. Legally considered a simple electronic signature format; it does not guarantee signer identity and can be easily forged.
- Tokens — although considered a form of digital signature, tokens are primarily used in the banking sector today.
What file formats can be signed electronically?
A common related question is: which document file formats support electronic signatures? The answer is broad. Almost any digital document can be signed electronically, but PDF is by far the recommended format — it is stable, universally compatible, and can embed multiple signatures securely.
Supported file formats include:
- PDF (strongly recommended); supports PAdES (PDF Advanced Electronic Signatures), a format specifically designed for long-term legal validity
- Word (.docx) — sign Word documents electronically
- Images (JPEG, PNG)
- XML files
For the highest legal certainty, especially with advanced or qualified signatures, always sign documents in PDF format.
>> Related resource: Sign PDFs electronically with Signaturit
Applications and use cases of electronic signatures
Today, numerous instances of the practical application of electronic signatures exist across formats. We can mention the following examples:
- The use of electronic signature formats for all kinds of contracts: in the labour, commercial, or administrative areas, among others.
- To verify receipt of documents by their final recipient. In this case, the unequivocal identification of the signatory provided by advanced or qualified formats is necessary.
- To carry out all kinds of public administration procedures, such as:
- Presenting tax declarations or fee payments.
- Enrolling in selection processes for public-sector employment.
- Consulting administrative records.
- Participating in bids for public contracts.
- Filing annual accounts with the Commercial Registry.
Uses of electronic signature formats by sector
| FACILITY SERVICES ✅ Temporary and permanent employment contracts ✅ Occupational risk prevention ✅ Receipts for equipment delivery | REAL ESTATE ✅ Rental contracts ✅ Reservation and deposit contracts ✅ Private sales contracts | INSURERS ✅ Insurance policies ✅ SEPA mandates ✅ Account or address change forms |
| HUMAN RESOURCES ✅ Employment offers ✅ Temporary and permanent employment contracts ✅ Personal data protection contracts | SALES TEAMS ✅ Sales contracts ✅ Purchase orders ✅ Service provision contracts | LEGAL DEPARTMENTS ✅ Minutes of boards of directors ✅ Shareholders’ meetings ✅ Partner agreements and investment contracts |
>> Related post: The 5 most frequently e-signed documents by our clients
How to choose the right electronic signature format
Not every document requires the same level of security. Matching the electronic signature format to the transaction’s risk level is both a best practice and a compliance requirement. Here is a simple decision framework:
| Risk level | Recommended format | Typical use cases |
|---|---|---|
| Low | Simple electronic signature | Internal approvals, newsletter consent, low-value orders |
| Medium–High | Advanced electronic signature | Employment contracts, NDAs, sales contracts, insurance policies |
| Highest / Regulated | Qualified electronic signature | Notarial acts, financial contracts, cross-border EU transactions, regulated industries |
When in doubt, the qualified electronic signature format offers the strongest legal protection: it eliminates the need to prove validity in court, as it benefits from automatic legal presumption under eIDAS.
Advantages of using electronic signatures
As seen from the examples and formats above, the advantages of electronic signatures over handwritten ones are significant:
Speed and efficiency
Thanks to electronic signatures, completing all kinds of procedures can be accelerated. Not only are travel and postal mail avoided, but the automation of signing and sending documents is also made possible. Industry research shows that up to 80% of agreements are completed in less than a day with e-signature solutions, compared to weeks with paper-based processes.
Cost savings
Savings come from reduced travel, postal services, and office supplies, as well as from the increased speed and automation of the process. Studies indicate that businesses can reduce operational costs by up to 37% after implementing electronic signature solutions.
Legal security
The legal certainty provided by an advanced or qualified electronic signature format can exceed that of the traditional handwritten signature. It makes forgery significantly harder and prevents the integrity of the signed document from being compromised. The qualified format, in particular, carries automatic legal presumption under EU law — meaning it is valid by default, without requiring additional proof in court.
Improved user experience
The convenience, speed, and efficiency of the e-signature process are highly appreciated by users. For businesses, this translates to higher conversion rates and reduced transaction abandonment, especially in digital sales and onboarding flows.
>> Related post: How electronic signatures improve the customer experience
Environmental benefits
The elimination of paper and the reduction of transport-related emissions are tangible environmental benefits of moving to digital electronic signature formats.
Frequently asked questions about electronic signature formats
Are all electronic signature formats legally valid?
Yes: simple, advanced, and qualified electronic signatures are all legally recognized under eIDAS in the EU. However, their evidentiary weight differs significantly. The qualified format has the highest legal standing and is equivalent to a handwritten signature by law.
Which electronic signature format is right for my business?
It depends on the risk level of the documents you are signing. For most business contracts, the advanced electronic signature format offers the best balance of security, legal standing, and ease of use. For regulated industries or high-value transactions, the qualified format is recommended.
What is the difference between an electronic signature and a digital signature?
A digital signature is a specific cryptographic implementation used within advanced and qualified electronic signature formats. All digital signatures are electronic, but not all electronic signatures are digital. Learn more in our dedicated article.
Which file format should I use for e-signed documents?
PDF is the strongly recommended file format for electronically signed documents. It supports PAdES, the standard for long-term legally valid electronic signatures, and is universally compatible across devices and systems.
Conclusion
Choosing the right electronic signature format (whether simple, advanced, or qualified) is a key business decision that affects both legal compliance and operational efficiency. As seen from the examples and use cases in this article, there is an electronic signature format for every industry and every risk level.
Technological advances have addressed the limitations of early solutions, and the widespread adoption of electronic signature formats across sectors is now a reality that continues to grow.
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