Signing documents electronically: a comparison of signature types

Electronic signatures have become an integral part of business processes for many companies. For departments such as Legal, Operations, or Compliance, the focus is not just on avoiding paper. Instead, faster approvals, traceable processes, and legally secure evidence are required.

Typically, various requirements converge here:

• Contracts should be signed promptly, often by parties at different locations
• Documents exist in different formats, e.g., as Word files or PDFs
• Legal questions regarding electronic signatures and regulations from the GDPR must be fully clarified

To meet these requirements, it is worth taking a closer look at signature types, standards, and typical use cases.

An electronic signature is any digital form of consent linked to a document. This can be a scanned signature, a signature drawn with a stylus on a tablet, a click on “Sign,” or a qualified electronic signature with a certificate. The key factor is that it documents the signer’s intent and is directly linked to the document. The choice of method depends on the requirements of the specific process.

Importantly, an electronic signature is not automatically the same as a digital signature. Legally, the electronic signature describes the act of signing. The digital signature typically refers to a technical method that uses cryptographic procedures, certificates, timestamps, and integrity checks. A digital signature can thus enhance the security and evidentiary value of an electronic signature.

For companies, this means: Not every document requires the highest signature level. The decisive factor is whether a process requires simple consent, reliable identification of the signer, or a legally valid signature.

Electronic signatures offer advantages especially where many documents, multiple parties, or recurring approvals are involved.

Typical benefits include:

• Faster processing times: Contracts no longer need to be printed, sent by mail, signed, scanned, and filed again.
• Better traceability: Audit trails, timestamps, IP data, identity verification, and signature certificates document the signing process.
• Fewer media disruptions: PDF documents, Word files, and forms can be edited and signed online.
• Enhanced compliance: Role-based workflows, mandatory fields, approvals, and archiving support internal guidelines and GDPR requirements.
• Higher process security: The integrity of the document can be technically ensured. Changes after signing are detectable.
• Better scalability: Legal and Operations teams can manage standard agreements, NDAs, supplier documents, or approval processes more efficiently.

Specialist departments benefit from the fact that electronic signatures not only digitize the signature but also structure the entire signing process.

Electronic signatures are particularly suitable for processes where documents need to be regularly reviewed, approved, or signed. These include, for example:

• NDAs and confidentiality agreements
• Supplier contracts and orders
• Data processing agreements
• Internal approvals and policies
• HR documents, where legally permissible
• Quotations, order confirmations, and service agreements
• Powers of attorney, declarations, and forms
• Government and administrative processes
• Customer onboarding and identity processes

If you want to sign documents electronically yourself, you can often use a tool in simple cases that allows you to insert a signature and save the PDF. If a document needs to be sent to other parties for signature, a professional solution becomes more important: It manages signers, sequence, fields, reminders, and secure storage.

An electronic signature can be legally valid. The central framework in the EU is the eIDAS Regulation. It defines different types of signatures and regulates the legal effect of electronic signatures.

Importantly, an electronic signature cannot be rejected solely because it is electronic. However, its specific evidentiary value depends on the signature level, identity verification, audit trail, and the respective legal transaction.

The eIDAS Regulation distinguishes three types of electronic signatures:

Simple Electronic Signature, EES

The simple electronic signature offers a low level of trust. Examples include a scanned signature, a click confirmation, or an inserted signature image. It is particularly suitable for internal approvals, simple agreements, or low-risk documents.

Advanced Electronic Signature, FES

In contrast to the simple electronic signature, the advanced electronic signature is uniquely linked to the signer and thus offers a higher level of security. This is ensured through authentication of the signing person, for example, via SMS or a phone call. Suitable use cases include B2B contracts, quotations, or NDAs.

Qualified Electronic Signature, QES

The qualified electronic signature according to eIDAS regulation offers the highest level of trust and security. It is based on a qualified certificate and a qualified signature creation device. Legally, it has the same effect as a handwritten signature. The QES is typically used for documents that require particularly high evidentiary value or must comply with written form requirements.

It is important to know that a simple signature may suffice if the risk and the value of the dispute are low. An FES is the better choice when precise evidence or document integrity is required. The QES is suitable when the legal written form is to be replaced electronically and no legal exception applies.

Departments should therefore not commit to a single signature level but should align the standard with the document or process.

A qualified electronic signature is particularly relevant when a document requires written form by law and this written form may be replaced by the electronic form. In Germany, this is particularly derived from § 126a of the German Civil Code (BGB). All signing parties must use a qualified electronic signature.

Typical cases may include certain agreements, declarations, or form-bound documents. However, it is important to note: Not every document requiring written form may be replaced electronically. Some legal transactions exclude the electronic form. A well-known example is the termination of employment relationships under § 623 BGB; here, the electronic form is not permitted.

For legal teams, this means: Before selecting the signature standard, it should be checked whether the document involves free form, text form, written form, or a legally excluded electronic form.

In addition to the legal signature types, there are technical standards for digital signatures. Particularly relevant are:

PAdES: Signature standard for PDFs. It is frequently used when a PDF needs to be digitally signed.

XAdES: Signature standard for XML documents.

CAdES: Signature standard for any digital files.

For specialist departments, PAdES is particularly relevant because many contracts are sent as PDF files. Tools such as Adobe Acrobat, Acrobat Reader, DocuSign, Skribble, or specialized signature platforms can support different signature levels depending on their functionality.

Providers like Skribble are often considered in practice when companies want to integrate electronic signatures with varying levels of trust into existing contract or approval processes. Buttons like “Sign” or “Click to Sign” are only the visible surface – what matters is the level of trust implemented in the background. The key is not just the tool itself but which signature type, identity checks, and audit functions are actually used.

When evaluating well-known providers like DocuSign or Skribble, Legal and Operations teams should therefore not only focus on the user interface but also on eIDAS compliance, the location of data processing, the issuer of the certificates, or integration options into existing processes.

The exact process depends on the electronic signature software. Typically, the process works as follows:

1. Upload document: Usually, a PDF is uploaded to the tool. Depending on the solution, uploading Word documents or other formats may also be possible. Many applications allow loading the file directly from local storage, a DMS, or a cloud application.
2. Edit fields: Signature fields, date fields, text fields, or roles are filled in by the signer. Clearly labeled fields in the right place prevent queries and reduce errors in the process. Additionally, each field should be uniquely assigned to a person or role to keep the signing process traceable. Mandatory fields ensure that no relevant information is missing before the document is completed.
3. Invite signers: The individuals usually receive an email with a link that directs them to the signature provider’s platform and the document. Many providers allow external individuals to sign without registration.
4. Verify identity: Depending on the signature type, a simple confirmation, a two-factor procedure via SMS or call, or identification with a valid ID document is performed.
5. Sign: The person signs electronically, for example, by clicking, using a stylus, a personal certificate, or a QES procedure.
6. Download document: After signing, the document, including the audit trail, timestamp, and signature information, is saved and can be downloaded by all parties.

Multiple parties can sign a document electronically. Professional solutions support parallel, sequential, and role-based processes. For example, Legal can review first, followed by Procurement signing, and then the external party.

In practice, PDFs are primarily signed electronically because they can be easily fixed and protected with digital signatures. Word documents can also be used depending on the application but are often converted to PDFs before signing.

If you only want to insert a simple signature, you can create a signature in programs like Adobe Acrobat or on a Mac, draw it with a stylus, insert it as an image, or scan a handwritten signature. A scanner or smartphone camera can also help create a signature file.

For simple internal processes, this may suffice. However, for contract-relevant documents with requirements for evidence, compliance, or integrity, such an approach is often too weak because identity, integrity, and validity are only limitedly secured.

There are free ways to sign documents electronically. These include features in PDF readers, Adobe Acrobat Reader, built-in Mac functions, or simple online tools. Users can insert a signature, edit existing fields, save a PDF, and send it via email.

Compared to traditional paper processes, this saves time but does not automatically replace reliable evidence or a structured compliance review. Free signatures are often sufficient for:

• Internal approvals with low risk
• Informal confirmations
• Simple documents without written form requirements
• Situations where high evidentiary value is not required

A professional signature solution is advisable when multiple parties are involved, when an audit trail is needed, when compliance regulations exist, or when documents need to be processed in a legally secure manner. Providers like DocuSign or Skribble can offer more features depending on the configuration than simple PDF or paper workarounds.

A QES is generally not free. Since qualified certificates, identity verification, qualified trust services, and secure signature creation are required, costs usually arise per signature, per user, or within a platform model.

When selecting an electronic signature solution, departments should not only focus on user-friendliness. Legal, technical, and organizational criteria are crucial:

• Are EES, FES, and QES supported?
• Are eIDAS-compliant signatures and qualified certificates possible?
• Is there a complete audit trail with a timestamp?
• Is the integrity of the document protected?
• Can multiple signers, roles, and sequences be mapped?
• Can PDF and Word documents be processed?
• Are there interfaces to contract management, DMS, CRM, or specialist procedures?
• Where are data stored and processed?
• Are data protection, information security, and company requirements met?
• Are GDPR requirements considered, such as for order processing, storage location, deletion periods, and access control?
• Is the use for external individuals easy to understand?
• Are all necessary fields available, and can they be customized?

Especially Legal and Operations should define signature standards according to risk classes: simple signature for low risks, FES for business-critical standard contracts, QES for form-bound or particularly sensitive processes. It should also be checked whether the chosen solution meets the company’s GDPR requirements and whether sensitive contract data is adequately protected.

Signing documents electronically does not simply mean inserting a scanned signature into a PDF. For companies and authorities, it is about the appropriate signature standard, traceable processes, integrity, identity, evidentiary value, and legal classification according to eIDAS.

SIGN8 supports companies and authorities as a qualified trust service provider in the field of Trust Infrastructure, Trust Services, digital identities, electronic signatures, seals, and EUDI Wallet readiness. This makes it possible to implement regulatory requirements and trustworthy digital processes practically and straightforwardly.

SIGN8 provides technical solutions and qualified trust services but does not replace legal review by the competent authority.