Even in the case where one party signs a contract just before another (so. Offer and acceptance does not always need to be expressed orally or in writing.1 Essential elements of a valid contract. The following elements are needed to form a valid contract: Agreement, i.e. This module guide is designed to help you to study the Contract law of England and Wales. A contract is formed when the offer is accepted without (changes) (additions). Consent is required for acceptance. In other words, it's illegal for someone to accept an offer when they're signing a contract with a gun pointed at them. However, a valid offer and acceptance only constitutes an agreement.