Landlord Tenant Agreement
Conventions and Treaties signed by signatories of states bind private actors to the terms of that agreement through the domestic application of the treaty provisions. These agreements may be bilateral (between two countries/states) or multilateral (between three or more countries/states).
Legal Contracts - Under state laws, only a few category of contracts must be in writing, such as a mortgage contract or contracts covering more than a year. It's still a good idea, however, to have a written agreement for business transactions beyond an ordinary sale of goods. There is no law requiring a lawyer to write your contract. If the transaction is relatively simple, the contract can also be simple. But you also have to pay attention to certain details to avoid issues arising later.