Hello everyone I would like to know if it is possible to create a robot and deployed on a website to interact with users.
Yes it is possible to create an automated responder (bot) and display on a web page.
As Steve says, there are lots of ways to do that. Many of them don't involve Node-RED. For example, Microsoft have a very comprehensive bot framework on Azure.
If you are wanting to involve Node-RED however, you will most likely be looking to use Node-RED to support the interactions and there are a number of nodes that may help. For example, have a look on the flows site for the stand-alone Rivescript node. Rivescript is a tool for creating flexible bot interactions. I use it for my home automation Telegram bots.
Just be aware that writing bots is hard work. Detailed and complex. Fun though.