A contract that must be in writing is an agreement between two or more parties, where the terms and conditions of the agreement must be expressed in written form. This type of contract is often used to ensure all parties involved fully understand their rights and obligations, as well as to provide an enforceable document that can be referred back to in the event of disputes or disagreements. The contracts should contain specific details such as names and contact information of the parties involved, a list of goods/services provided, applicable payment terms, delivery timelines, etc. to eliminate any misunderstandings and potential conflicts.