there is a section in the core docs about just that (link.)
There is also a custom channel that’s part of the Scalablemind’s Chatroom webinterface here (line 58 onwards) - though I wouldn’t use that in production.
@soundaraj I assume since Rasa is for conversational bots, you’re looking to connect your bot to twitter DMs – here’s the twitter Direct Message API which should help you get started!