Developing with the web application Node.js. About the real-time consultation function.

Web application is being built with node.js. Following my studies, I am developing it for service purposes.

On the main page, I would like to implement the function shown below. The site below is a screen from Lawn Messenger (https://www.jandi.com/landing/kr.

I want to implement the function indicated by the arrow, but I don't think it's possible to ask for a development method here, and I'm curious about the keyword so that I can find and develop it.

Thank you for your interest and reply.