This bot is designed to help people find answers related to COVID-19. You can simply ask any question and the Bot is trained to respond. Botcopy offers a service to train the bots and create valuable resource to answer any question.
The chat on this site is built by an open source project called "web experience toolkit" - Its not an NLP system, but have done a good job answering questions. This page is directed from a botcopy chatbot.
Ada is a conversational chat platform similar to Dialogflow. The chatbot on their site offers a great example of how to build a conversational chatbot. Offer information first and get the users interest before asking for their info.