Final answer:
A valid contract must contain an offer made by one party and an acceptance by another, which are the essential components of any agreement. Not all contracts need to be filed with the state or witnessed by an attorney, and while some must be in writing, the core requirement is the mutual consent of the parties involved.
Step-by-step explanation:
In order for a contract to be valid, it must contain an offer and acceptance. This is a fundamental principle of contract law, which states that there must be a clear offer by one party and an unambiguous acceptance by another. Contracts do not necessarily need to be filed with the state, nor do they require witnessing by an attorney to be valid, although some types of contracts, like real estate deals, do often need to be in writing and notarized. However, the essence of a contract is the agreement between parties to perform certain obligations spelled out within the agreement.