1. An offer and acceptance are required to form a contract. An offer involves making a proposal to another party (the offeree). When the offeree signifies their assent to the proposal, it becomes an acceptance and a promise.
2. For a valid offer, the terms must be clear and definite, it must be communicated to the offeree, and it can be revoked any time before acceptance but not afterwards. An acceptance must be absolute and unconditional for a contract to be formed.
3. An offer lapses when revoked, the time period expires, or a condition precedent is not met. An acceptance can only be revoked before the acceptance reaches the offeror's knowledge.