Contract law is a specific area of the law that specializes in contracts. Just as doctors specialize in certain areas of medicine, there are some lawyers who specialize in contract law.
Contract law focuses on making agreements that are legally binding. Then, contract law also enforces those agreements to make sure parties do what they say they will do. Agreements are an important part of everyday life, and you may sign an agreement with a business if you purchase something expensive.
Or, if you decide to work for someone, you will sign a contract that specifies the scope of your duties as well as your compensation. Essentially, a contract is a way of formalizing an agreement you make with another party. Both parties who sign the contract are expected to adhere to it.