You can agree to a contract with any clear manifestation of intent. (lawyerist.com)
Independent legal advice reduces the likelihood that a party to the agreement succeeds in challenging the contract's validity after agreeing to the contract. (familylawyerdivorcetoronto.com)
Is it so that latter in a dispute, if a person claims they never agreed to the contract, their signature could be used as evidence that they did? (law.stackexchange.com)