When two or more then two persons want to start a business together as partners for profit by investment, they sign a legal document which called partnership contract. This contract spells out all right & obligations and other terms & conditions of partnership regarding their business. That may be amount of investment, nature of business, duration of partnership, profit and other specific information. It is necessary to prepare this contract for protections of their business relationship and avoiding all other problems and troubles when this relationship may ends. It is most important for both business parties, so that is the reason it must be in written and signed by both. It may be used by individuals or by companies.