The Contract Act 1872 outlines essential elements for a valid contract in India. A contract requires an offer and acceptance, consideration, lawful purpose, capacity to contract, free consent between parties. An offer must be definite and communicated to the offeree. Acceptance must be unconditional, communicated to offeror, and within a reasonable time. If any essential element is missing, an agreement is void. The Act also defines different types of contracts based on validity, formation, and performance. It provides rules for offer, acceptance, and discharge of a valid contract.