Is there any legal agreement about passing your business to another party?

We have a family business, a feed retailing and merchandise to be exact. We have decided to pass this business to someone my dad trusts and has a branches of the same business field. I would just like to ask about the contract, what kind of agreement is it? We are thinking about the contract good for a year for a trial. I would appreciate your response. Please email me espiloykaycee14@gmail.com