What is a smart contract? How do they work? What are they good for ??

A smart contract is an agreement between two or more parties in the form of computer code. The contracts are stored on the blockchain and cannot be changed. Transactions that take place in a smart contract are processed by the blockchain, which means they can be sent automatically without the intervention of a third party. When you enter into an agreement with a smart contract, no confidential advisor is required. The transactions only take place if the conditions in the agreement are met. Hope this helps!