if you want , you can create a web widget with the help of Bot Framework , from azure portal you can host it anywhere you can.(skype,facebook or web widget etc)
You will have to run your bot as a http server (for that you can go to rasa core docs).
Then you will just have to make a HTTP request to your rasa bot server .
I am attaching a gist link with sample code you just have to add your app id and password which you will get from the project settings, which you will create on azure portal and custom your rasa http server url according to your bot’s requirement