Chatbot enables the business people to reach their target customers using popular messenger apps like Facebook, Whatsapp etc. Chatbots are not handled by humans directly. Nowadays, Chatbots are becoming very popular especially in business sector by reducing the human efforts and automated customer service. It is a software which interacts with user using natural language processing, Machine Language and Artificial Intelligence. They allow users to simply ask questions which would simulate interaction with the humans. The popular and well known chatbots are Alex and Siri. This paper focus on review of chatbot, history of chatbot and its implementation along with applications.