Updated July 2026 · 8 min read
Signing a contract PDF takes under a minute. Deciding whether you should sign it — and whether you are the right person to sign it — deserves longer. This guide covers what makes a commercial agreement binding, who can commit an organisation to one, how to complete a signature block, and the clauses worth reading twice.
A contract binds because the parties reached an agreement the law will enforce, not because someone signed. The signature is evidence that a named person assented to particular words on a particular date. Hence an exchange of emails can commit you before the formal document appears. For the position country by country, see our guide to electronic signature laws.
Common-law jurisdictions analyse formation through broadly these elements. Civil-law systems arrive somewhere similar by a different route; the clearest divergence is consideration, which they generally do not require.
A proposal definite enough to be accepted as it stands. Price lists and tender invitations are usually invitations to treat, not offers.
Unqualified assent to the terms offered. Change a term and you have made a counter-offer — hence the 'battle of the forms'.
Each side must give something of value; courts test that it exists, not that the deal was good. A common-law requirement only, and deeds can bind without it.
Presumed between businesses, not in social arrangements. Documents marked 'subject to contract' try to rebut it, but are judged on substance.
Each party must be legally capable of contracting. Under the UK Companies Act 2006, a company's act is not invalid merely because of something in its constitution — modern statutes largely protect a good-faith counterparty.
Unlawful agreements are unenforceable, and so is an 'agreement to agree'. Vague terms like 'at a price to be agreed' cause most certainty problems.
In the US, the Uniform Commercial Code's statute of frauds on sales of goods (§ 2-201) requires a signed writing at or above a threshold price — $500 in the model text. In England and Wales, contracts disposing of an interest in land need a signed written document under section 2 of the Law of Property (Miscellaneous Provisions) Act 1989, and guarantees must be evidenced in writing under the Statute of Frauds 1677. And where an individual signs a deed under English law, a witness must attest the signature.
The most common signing mistake in business is not a missed clause. It is the wrong person putting their name in the box, or the right person putting it there in a way that exposes them personally.
Actual authority is what a person has genuinely been given — by statute, the constitution, a board resolution or a power of attorney. Apparent authority is what the other side may reasonably infer from how the organisation held that person out: a business can be bound by an employee who broke an internal rule, if the counterparty acted in good faith. Delegated authority is actual authority pushed down through an approval matrix with thresholds by role.
The block must show the entity that is contracting, that you sign on its behalf, and the role giving you authority. Agency law is unforgiving about ambiguity: an agent who signs without making the principal clear invites the argument that they contracted personally.
If the block omits the entity name or your title, add them as text before signing — that completes the block rather than altering agreed terms.
If the block names a colleague, do not sign over their name. Ask for a page naming you and your title.
That phrase changes the formalities, the witnessing requirement, and in England and Wales the limitation period for claims.
A witness must observe the signing and complete their own name, address and signature. The other contracting party is not a safe choice.
A document you have signed and they have not is an open offer, not an agreement.
An undated contract hands the other side control over when obligations start. Date it and confirm by email.
Missing initials rarely invalidate an agreement, but they invite the argument that a page was substituted.
Read the schedules before the main body. Disputes turn far more often on what was promised and when payment falls due than on the boilerplate at the back.
Full registered names, entity type, company number and registered address — not trading names. Contracting with the wrong company in a group is expensive: it may hold no assets.
What is in scope, what is out, and what the supplier assumes about your inputs. A fixed commitment, 'best endeavours' and 'reasonable endeavours' are three different promises.
Who decides the work is done, tested against what, and what happens on rejection. Deemed-acceptance wording that treats silence as approval shifts risk onto whoever is busiest.
Amount, currency, tax treatment, invoice triggers, payment period and set-off rights. Statutory backstops for late payment include the UK Late Payment of Commercial Debts (Interest) Act 1998, EU Directive 2011/7/EU as implemented locally, and India's MSMED Act 2006 for registered micro and small suppliers — rates are set by regulation, so verify current figures. Cap expenses too.
Separate background IP from what is created under the contract, then decide whether new IP is assigned or licensed. If licensed, check scope, territory, sublicensing and survival after termination. Copyright assignments generally need signed writing in the UK and the US.
Duration, permitted recipients, return or destruction, and the carve-out for disclosures required by law. Check whether this contract supersedes an earlier NDA with weaker terms.
Reviewing an NDA clause by clause →Warranties are statements promised to be true: authority to contract, reasonable skill and care, no third-party infringement. An indemnity goes further — a promise to reimburse defined losses, often sitting outside the liability cap. Ask what triggers it, whether it is capped or mutual, and who controls the defence.
Is the cap per claim or aggregate, a fixed sum or a multiple of fees? Read the exclusions of indirect loss and lost profit. Death or personal injury caused by negligence, and fraud, normally sit outside the cap; in the UK the Unfair Contract Terms Act 1977 makes such exclusions ineffective and subjects many others in standard terms to a reasonableness test.
What cover, at what level, on what basis. Occurrence and claims-made policies behave very differently after a contract ends, so check run-off cover and certificate requirements.
Termination for convenience lets either side walk on notice, sometimes with a break fee; termination for cause needs material breach, a cure period or insolvency. Check surviving licences, and diarise any auto-renewal notice deadline the day you sign.
Who must be notified, at what address, by what method, and when notice is deemed received. Many contracts exclude email for formal notices — a termination notice sent the wrong way is often no notice at all.
Governing law and jurisdiction are separate choices, and exclusive jurisdiction differs from non-exclusive. If arbitration is chosen, check the seat, rules and language. Arbitral awards are generally easier to enforce abroad than court judgments, under the widely ratified 1958 New York Convention.
An entire agreement clause shuts out prior drafts and sales promises, so anything you relied on must appear in the contract; it generally cannot exclude liability for fraud. A no-oral-modification clause means changes need signed writing. An order-of-precedence clause decides whether the main body, the schedules or standard terms win.
A counterparts clause says the contract may be signed in separate copies, each an original, together forming one agreement. Without it, a counterparty can argue that no single document bears both signatures.
An electronic signature clause records that both sides agree to sign and deliver electronically, and that an electronically signed PDF has the same effect as an original. It does not create validity — legislation does that — it removes the argument. The US UETA applies between parties who have agreed to transact electronically; the EU eIDAS Regulation (EU) 910/2014 prevents an electronic signature being denied legal effect purely for being electronic; the UK Electronic Communications Act 2000 provides for admissibility in evidence.
One caution: established English practice for virtual signings is that a signatory should sign the final agreed version of the whole document, not a loose page attached to it later.
Almost every ugly contract argument that is not about money is about which version was signed. Negotiation leaves a trail of files named Agreement_v3_final_FINAL_JL.docx, and the PDF you sign may not be the one you last negotiated.
Crossing out a clause and initialling the margin is historically accepted practice and a bad habit today: a manuscript amendment binds only if the other party actually agrees to it, and on a PDF sent by email it is often unclear whether they saw it. Raise the change in writing first and ask for a corrected execution version. If it cannot be avoided, strike through rather than obliterate the original wording, have every signatory of every party initial beside it, and flag it in your covering email. Never change anything after the other side has signed.
SimpleSignPDF produces a Simple Electronic Signature. Your signature and text are drawn into the page content of the PDF, so they form part of the page rather than movable annotations a later reader can drag away. For most everyday commercial agreements, that is legally sufficient.
The limits matter just as much. It does not verify who you are and does not produce an audit trail — no timestamp certificate, no IP record, no email-verification log. It applies no cryptographic digital signature, and it cannot send a document to a counterparty for signature. If the contract is high-value or contentious, if you need a Qualified Electronic Signature under eIDAS, or if a document must be routed through several signatories, use a dedicated platform — our comparison of self-signing tools and signature platforms sets out where the line falls. Vendor features and pricing change often, so check their own sites rather than any comparison article.
How long to keep it depends on where you are. In England and Wales the limitation period for a claim on a simple contract is six years from the breach, and twelve years where the contract was executed as a deed. In the United States periods are set state by state, and the Uniform Commercial Code sets a separate one for sales of goods. Keep contracts for the longest applicable period, measured from the end of the contract rather than the signature date.
Both can. A sole trader signs personally, exposing personal assets. A company signs through an authorised individual, and the block should name the company, the signatory and their role. Deeds attract extra formalities, such as two authorised signatories or a witnessed director signature.
You can still sign it — SimpleSignPDF works with any valid PDF, including scans. But a scan is a picture: you cannot search it or compare it against the version you negotiated. Ask for the text-based PDF if the deal matters.
Ordinary commercial contracts do not; deeds normally do. Under English law a deed signed by an individual must be signed before a witness who attests the signature, and remote signing does not remove that.
Yes, and raise them before signing rather than annotating the PDF. Set out each change in writing; if the other party agrees, ask for a revised execution version. Marking up after signing produces a document whose terms are unclear.
It depends how things looked to the other side. With apparent authority your employer may be bound despite an internal rule. If your lack of authority was clear, the company may not be bound and you could face a claim for breach of warranty of authority.
Related reading: Electronic signature laws by country · How to sign an NDA · How to sign a rental agreement · How to sign a PDF online