Signatures appear on everything from a supplier quote to a multi-party deed, yet most business owners have never had to think carefully about what actually makes one legally valid. In Australia, the rules are more flexible than many people assume — but there are real traps that can leave a document unenforceable or give the other side an argument that no binding agreement was ever reached.
This article explains what the law treats as a valid signature, the specific requirements that apply when a company signs, how electronic signatures work under Australian law, when witnesses and initialling are needed, and where the most common mistakes occur. The following topics are covered:
- What counts as a signature in Australian law
- When a signature is legally required
- How companies execute documents — including under s 127 of the Corporations Act 2001 (Cth)
- Electronic signatures and the Electronic Transactions Act 1999 (Cth)
- Deeds and their additional formalities
- Common mistakes and how to avoid them
What Counts as a Signature
A signature is a mark made by a person to demonstrate their identity, their agreement to the contents of a document, and their intention to be legally bound. The mark does not have to be a cursive autograph.
Australian courts look at the function of the mark rather than its form. A valid signature can be:
- Wet ink — a handwritten name, initials, or mark applied directly to paper.
- Electronic signature — a typed name at the end of an email, a scanned image of a signature inserted into a PDF, a click of an "I accept" button, or a finger or stylus drawing on a touchscreen.
- Digital signature — a sub-category of electronic signature that uses cryptographic technology (typically provided by a dedicated e-signature platform) to verify both the identity of the signer and the integrity of the document after it was signed.
What matters across all three forms is that the signature is reliably linked to the person who made it and that person demonstrated a clear intention to be bound by the document at the time of signing.
When Is a Signature Legally Required
Most contracts between businesses in Australia can be formed verbally or by conduct — a signed written document is not always a legal precondition of a binding agreement. That said, certain documents and transactions do require specific execution formalities:
- Documents executed under the Corporations Act 2001 (Cth) — a company that wants to take advantage of the statutory presumptions in s 129 of the Act will generally execute documents under s 127.
- Deeds — deeds are formal instruments that do not require consideration to be binding, but they carry stricter signing and delivery requirements than ordinary agreements.
- Documents required to be witnessed or notarised under state and territory law — for example, certain statutory declarations and some property-related instruments.
Even where no law strictly requires a signed document, a signed written agreement is best practice because it provides clear evidence of what was agreed and reduces the scope for later disputes about terms.
How Companies Execute Documents
A company is a separate legal entity and cannot sign in the way an individual can. The Corporations Act 2001 (Cth) sets out a mechanism for companies to execute documents that carries a statutory presumption of due execution.
Execution under section 127
Under s 127 of the Corporations Act 2001 (Cth), a company may execute a document without a common seal if it is signed by:
- two directors of the company; or
- a director and a company secretary; or
- for a proprietary company with a sole director who is also the sole company secretary, or who is the sole director and the company has no company secretary — that person alone.
The third point reflects an amendment that took effect from 1 April 2022, which resolved a long-running gap in the law: before that amendment, a single-director proprietary company could not rely on s 127 to execute documents unless the director also held the office of company secretary.
Execution under s 127 is not the only way a company can sign a document, but it is the most straightforward because it gives counterparties the protection of the statutory assumptions in s 129 — including the assumption that the document was duly executed. Where execution is by authorised representative rather than under s 127, the counterparty cannot rely on those assumptions and should independently verify the representative's authority.
Execution by authorised representative — section 126
Under s 126 of the Corporations Act 2001 (Cth), a company's power to make, vary, ratify, or discharge a contract may be exercised by an individual acting with the company's express or implied authority and on behalf of the company. This is how a manager, employee, or external agent can sign a contract that binds the company without being a director or company secretary. The catch is that the authority must actually exist — a job title alone does not create signing authority.
Common seals
Common seals are optional; the vast majority of companies now execute documents without one using the methods described above.
Electronic Signatures and the Electronic Transactions Acts
At the Commonwealth level, s 10 of the Electronic Transactions Act 1999 (Cth) provides that a requirement for a signature under a Commonwealth law can be met by an electronic signature if:
- a method is used to identify the person and to indicate their intention in respect of the information communicated; and
- the method is as reliable as is appropriate given the purpose for which, and the circumstances in which, the communication was made; and
- the person to whom the signature is being given consents to that requirement being met by way of electronic signature.
Each state and territory has equivalent legislation — for example, s 9 of the Electronic Transactions Act 2000 (NSW) and s 9 of the Electronic Transactions (Victoria) Act 2000 — which apply the same framework to requirements arising under state and territory law.
Permanent technology-neutral measures for company execution under the Corporations Act took effect from 23 February 2022. These measures allow companies to execute documents electronically under s 127 — including by a combination of electronic and physical signatures across different signatories — provided the process satisfies the Act's requirements.
In practical terms, most standard commercial contracts can be executed electronically. Where a counterparty or a specific document type requires wet ink, that preference needs to be agreed and planned for at the outset of the transaction.
Deeds and Additional Formalities
A deed is a formal legal instrument used when consideration is absent, when the law requires it, or when the parties want the heightened formality and longer limitation period that deeds carry. Unlike a simple agreement, a deed is subject to stricter execution requirements.
For companies, the Corporations Act permits electronic execution of deeds under s 127 — the same mechanism as for agreements — provided the document is expressed to be executed as a deed. Under the 2022 amendments, delivery of a deed by a company is not required where the deed has been executed under s 127(1) or (2).
For individuals, deeds typically need to be signed, witnessed, and delivered. The witnessing requirements for individuals executing deeds vary somewhat between states and territories and should be confirmed against the law of the relevant jurisdiction.
If there is any doubt about whether a deed or a simple agreement is more appropriate for a given transaction, or about how to execute correctly in your jurisdiction, legal advice before circulation is the safest course.
Common Mistakes That Invalidate or Weaken Execution
The following are the most common signature-related errors that create risk for businesses:
- Assuming a title confers signing authority. A "General Manager" or "Operations Director" may not have legal authority to bind the company to a given contract. Delegations of authority need to be documented and communicated, and counterparties should ask for evidence of authority before relying on execution by a person who is not a director or company secretary.
- Signing a draft rather than the final version. If the document is amended after the signature page is prepared, or if the version circulated for signing is not the final agreed version, the execution may not reflect the actual agreement.
- Mixing execution methods without planning. If one party insists on wet ink but the other sends an electronic copy for signature, there can be ambiguity about which version is the binding executed document and whether delivery occurred at the right time.
- Omitting a counterparts clause. Where the parties are signing separate identical copies of the same document rather than one physical document, the agreement should include a counterparts clause confirming that each copy constitutes an original and that together they form a single binding instrument.
- Failing to satisfy witnessing requirements. Where a document legally requires a witness, the witness must be eligible under the applicable rules, must be physically present at the time of signing (unless a specific remote witnessing regime applies), and must complete all details in the witnessing block.
- Leaving blank fields or schedules. Blanks in a signed document can create genuine ambiguity about what was agreed and, in some cases, allow a party to argue the document is incomplete.
- Entity name mismatches. Signing in the name of the wrong entity — for example, using a trading name instead of the correct ACN-registered company name — can affect enforceability.
How Artificer Legal Can Help
Signature and execution questions often arise at the most time-sensitive point in a transaction — just before signing. The stakes are high: get it wrong and you may have no enforceable agreement, or you may have bound the wrong entity to a contract.
A solicitor at Artificer Legal can assist by:
- Reviewing your execution block and signature arrangements before a document is circulated.
- Advising on whether a document should be structured as a deed or a simple agreement given your circumstances.
- Confirming the signing authority of any person proposed to execute on behalf of a company or other entity.
- Drafting or reviewing delegation of authority policies so your team knows who can sign what, and up to what value.
- Identifying any document-specific requirements — witnessing, notarisation, counterparts clauses — before they become a problem.
Conclusion
A valid signature in Australian law is any mark that reliably identifies the signer, indicates their intention to be bound, and is made using a method the other party has accepted. The format — wet ink, electronic, or digital — matters less than whether those three elements can be demonstrated. For companies, the most reliable path is execution under s 127 of the Corporations Act 2001 (Cth), which carries statutory protections for counterparties and has been updated to accommodate electronic execution.
Key points to keep in mind:
- Wet ink and electronic signatures are both valid in most commercial contexts, subject to the consent and reliability requirements under the relevant Electronic Transactions Act.
- Companies should execute under s 127 where possible — two directors, a director and secretary, or a sole director of a proprietary company that has no company secretary.
- Authority matters: a title does not automatically confer signing authority; document delegations internally and verify them externally.
- Deeds carry additional formalities — use them when the law or transaction requires it, and take advice on execution before circulating.
- Common traps — wrong entity, unsigned draft, missing counterparts clause, blank schedules — are avoidable with a consistent pre-execution checklist.