You can send custom messages to the chatbot conversation of Message type based on a user action. This is done using the JavaScript API method, collectchat.message.

For example:

<a href="#" onclick="collectchat.message('Thanks for clicking the link')">This is a link</a>

This can be used to inform the user about the availability of an item or the price of an item based on the user interaction. You can track how user is responding to the questions using the collectchat.on method and then programatically send messages to the conversation using collectchat.message method.