What type of contract can be informal and may be written, oral, or implied?

The type of contract that can be informal and may be written, oral, or implied is a simple contract. Simple contracts are characterized by their flexibility and do not require any specific formality to be valid, which means they can be entered into through various means, including spoken agreements or written documentation.

This type of contract is often used in everyday transactions, where the parties involved may not go through extensive legal processes or stipulations. The key aspect of a simple contract is that it creates a legally binding agreement when all essential elements are present, such as offer, acceptance, and consideration. This distinguishes it from more formal contracts that might require a specific format or certain legal stipulations to be enforceable.

The other types of contracts mentioned have distinct characteristics: formal contracts typically require specific requirements, legally binding contracts can refer to any contract that is recognized by law, and executory contracts are those that have not yet been fully performed by one or all parties involved. Thus, the simple contract stands out for its informal nature and versatility in form.