How contracts are usually signed comes down to two methods: a handwritten signature on paper, or an electronic signature applied through a digital platform, a typed name, or a click on an “I agree” button. Federal law treats the two as legally equivalent for most transactions. What determines whether a signature actually binds anyone is not the medium but four other things: the signer has authority, the document type allows the method used, the signer intended to be bound, and any required witnesses or notarization are in place.
Physical Signatures on Paper
The pen-on-paper signature is still the baseline. You place a cursive mark on a designated line, ideally in permanent ink so it resists fading and tampering. If a signer cannot write, a simple “X” or other mark is acceptable in most situations, though having a witness present strengthens its validity. Rubber stamps reproducing a signature also see use in high-volume business settings, with the person who authorized the stamp remaining responsible for anything stamped in their name.
Physical signatures have one practical advantage that keeps them relevant: they work for every document type, everywhere. No law excludes them. No technology needs to function. When a real estate closing requires notarization or a will demands witnesses, the physical signature is the one method that never raises a compatibility question.
Electronic Signatures
The Electronic Signatures in Global and National Commerce Act, passed in 2000, established that an electronic signature is legally equivalent to a handwritten one for most transactions. The statute defines an electronic signature as an electronic sound, symbol, or process attached to a record and executed by a person with the intent to sign it.1Office of the Law Revision Counsel. 15 USC Ch. 96: Electronic Signatures in Global and National Commerce That definition is deliberately broad. A typed name, a click on an “I agree” button, a finger tracing on a tablet screen, or a scanned image of your handwritten signature all qualify.
Alongside the federal ESIGN Act, 49 states, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands have adopted the Uniform Electronic Transactions Act, which provides a parallel state-level framework. New York has not adopted UETA but enacted its own electronic signature statute with similar effect. Under both laws, two conditions must be met: all parties must agree to conduct the transaction electronically, and the signer must demonstrate intent to sign. The agreement to proceed electronically does not need to be a formal document itself. It can be implied by the parties’ conduct, such as exchanging drafts by email and then signing through a digital platform.
E-signature platforms typically generate an audit trail recording the signer’s identity, IP address, timestamp, and the specific version of the document signed. That trail becomes the primary evidence of who signed and when, which is why choosing a platform with tamper-evident records matters more than the specific type of electronic signature used.
Clickwrap and Online Agreements
When you check a box next to “I agree to the Terms of Service” before creating an online account or making a purchase, you are signing a contract. Courts have consistently held that these clickwrap agreements are enforceable, but only when the design meets certain standards. The core requirement is that users must receive reasonably conspicuous notice of the terms and take an unambiguous action to accept them.
In practice, that means the link to the terms must be visible rather than buried below a download button, and the user must affirmatively click or check something. Pre-checked consent boxes are treated skeptically because the user never made an active choice. Browsewrap agreements, where a company claims you agreed to terms simply by using the website without ever clicking anything, fare much worse in court. Unless the terms were so prominently displayed that any reasonable person would have noticed them, browsewrap agreements are frequently found unenforceable.
Courts also look at whether the terms themselves are fair. An agreement that reserves the right to change its own terms unilaterally, with no notice to users, risks being called illusory. Terms that exploit a massive imbalance in bargaining power can be struck down as unconscionable, even if the user technically clicked “agree.”
Documents You Cannot Sign Electronically
The ESIGN Act carved out several categories where electronic signatures do not apply. These exclusions exist because certain legal instruments carry consequences serious enough that lawmakers wanted to preserve the formality of physical execution.
- Wills, codicils, and testamentary trusts. These must be signed on paper, typically with witnesses, under the laws of every state.
- Family law matters. Adoption orders, divorce decrees, and similar documents governed by state domestic relations law fall outside the ESIGN Act.
- Most Uniform Commercial Code transactions. Negotiable instruments like checks and promissory notes, secured transactions, and documents of title are excluded. The exception is that sale-of-goods contracts and lease transactions under UCC Articles 2 and 2A can still be signed electronically.
- Court orders and certain consumer-protection notices, including utility shutoff warnings, foreclosure notices, insurance cancellation letters, and product recall documents.2Office of the Law Revision Counsel. 15 USC 7003: Specific Exceptions
If you are signing any document in these categories, use a physical signature unless you have confirmed that your state’s laws permit an electronic alternative.
When a Signature in Writing Is Required at All
Some contracts must be in writing and signed to be enforceable in the first place. The Statute of Frauds, adopted in some form by every state, covers several categories:
- Real estate transactions. Any contract to sell, transfer, or create an interest in land.
- Contracts that cannot be performed within one year of signing.
- Sale of goods worth $500 or more. Under UCC Section 2-201, the contract needs a written document signed by the party you want to enforce it against.3Legal Information Institute. UCC 2-201 Formal Requirements; Statute of Frauds
- Promises to pay someone else’s debt, including loan guarantees.
- Promises made in consideration of marriage, such as prenuptial agreements.
An oral agreement in one of these categories is not automatically void between the parties, but a court will refuse to enforce it if the other side raises the Statute of Frauds as a defense. There are narrow exceptions. For goods, if the buyer has already paid and the seller accepted payment, or the goods have been delivered and accepted, a court may enforce the deal even without a signed writing.3Legal Information Institute. UCC 2-201 Formal Requirements; Statute of Frauds Relying on those exceptions is a gamble no one should take deliberately.
Who Has Authority to Sign
Individuals
To sign a binding contract, you generally must be at least 18 and mentally capable of understanding what you are agreeing to. A contract signed by a minor is not automatically void, but the minor has the right to walk away from it. That makes the agreement voidable at the minor’s option, which puts the adult party in a weak position. Contracts signed under extreme duress or by someone with a significant cognitive impairment face the same vulnerability.
Signing for a Business
When a company signs a contract, some human being has to hold the pen or click the button. The question is whether that person had authority to bind the organization. Actual authority exists when the company’s bylaws, board resolutions, or operating agreement explicitly grant a particular officer or employee the power to sign. A CEO or president typically has this by default. Apparent authority arises when the company allows someone to act in a way that makes an outsider reasonably believe they can sign on the company’s behalf, even if no formal authorization exists internally.
If someone without any authority signs a contract on behalf of a company, the agreement does not automatically bind the company. But the company can ratify the unauthorized signature after the fact, either by explicitly approving it or by accepting the benefits of the deal with knowledge of what happened. Ratification makes the signature binding retroactively. The person who signed without authority can face personal liability to the other party.
Power of Attorney
An agent acting under a power of attorney can sign contracts on behalf of the person who granted it. The signature format matters. The agent should not simply sign their own name. The correct approach is to identify both the principal and the agent in the signature block, using language such as “Jane Smith, by John Doe as attorney-in-fact” or “John Doe, agent for Jane Smith.” Signing without disclosing the agency relationship can create personal liability for the agent and raise questions about whether the principal is actually bound.
The scope of the power of attorney also limits what the agent can sign. A limited power of attorney authorizing someone to handle a single real estate closing does not give them authority to sign an unrelated business contract. If a document exceeds the agent’s granted authority, the principal is not bound by it.
When Witnesses Are Required
Certain documents require one or more witnesses to observe the signing and add their own signatures. If a dispute arises later about whether the signature is genuine, whether the signer was coerced, or whether the signer understood what they were doing, the witness can testify about the circumstances. A witness should be a disinterested adult with no financial stake in the agreement. Someone who stands to benefit from the contract is a poor choice, and some jurisdictions will disqualify an interested witness entirely.
Requirements vary by document type. Wills almost universally require two witnesses. Real estate deeds need witnesses in some states but not others. Standard commercial contracts rarely require witnesses unless the parties voluntarily add them for an extra layer of protection. When witnesses are required, failing to include them can make the document unenforceable regardless of how genuine the primary signatures are.
When Notarization Is Required
A notary public is a state-commissioned official whose job is to verify the identity of the person signing a document. The notary checks government-issued identification, confirms the signer is acting voluntarily, and then applies an official seal or stamp along with their own signature and commission details. Real estate deeds, affidavits, and certain financial documents commonly require notarization. Without it, a recording office will typically reject the document, and a court may question its enforceability.
Many states require notaries to maintain a journal logging each notarial act, including the date, the type of document, the signer’s identity, and the method of identification used. Not all states mandate this, but the practice is standard enough that the absence of a journal entry can raise questions about whether the notarization actually occurred. Notary fees are regulated at the state level and typically range from a few dollars to $25 per signature, though some states set no maximum.
Remote Online Notarization
As of early 2025, 45 states and the District of Columbia have enacted permanent laws authorizing remote online notarization, which allows a signer to appear before a notary via live audio-video technology rather than in person. The notary verifies the signer’s identity through at least two methods, such as knowledge-based authentication questions combined with a review of a government-issued ID displayed on camera. The session is recorded and retained as part of the notarial record. Because the practice is not yet uniform, a document notarized remotely in one state may face recognition challenges in a state that has not authorized the practice.
Signing in Counterparts
When the parties to a contract are in different cities or countries, they do not need to gather around one table. Signing in counterparts means each party signs a separate but identical copy of the agreement, and together those individually signed copies constitute a single binding contract. Most agreements that anticipate this include a counterparts clause stating exactly that.
After signing, each party typically scans their signature page and sends it to the other parties or to a designated coordinator who assembles a master document containing all signature pages behind a single copy of the agreement text. The compiled version is the official executed record. This approach works equally well with physical and electronic signatures, and it eliminates the logistical headaches of shipping paper across time zones.
One practical note: the signature pages should reference the agreement clearly enough that they cannot be detached and reattached to a different document. Including the agreement title, date, and parties on or near the signature line reduces the risk of a later dispute about which version of the contract was actually signed.
What Happens When Signing Is Done Wrong
A flawed signature does not always destroy a contract, but it creates problems that range from inconvenient to fatal depending on the circumstances. If a contract that falls under the Statute of Frauds was never signed in writing, a court will decline to enforce it when the defense is raised. If a real estate deed was not notarized, the recording office will reject it, leaving the buyer with an unrecorded interest that is vulnerable to competing claims.
When someone signs without authority, the unauthorized signature does not bind the organization they claimed to represent. It does bind the person who signed. They face personal liability on the instrument, and the other party can pursue them directly if they dealt in good faith. The organization can choose to ratify the signature later, which makes it retroactively binding on the company, but ratification does not erase any civil or criminal liability the unauthorized signer may have incurred.
For electronic signatures, using an e-signature on a document that falls within the ESIGN Act exclusions means the signature has no legal effect under that statute.2Office of the Law Revision Counsel. 15 USC 7003: Specific Exceptions An electronically signed will, for example, would fail in virtually every state. The fix in most cases is straightforward: re-execute the document properly. The gap between the defective signing and the corrected one can create real exposure if rights were supposed to transfer or obligations were supposed to begin on the original date.