Mostly, we get the user request through the integration and pass it to your bot via our API.
We always deal with text input, and do the whole NLU - Dialog Management work, except for Alexa wich is only providing with the user intent.
Below is the data flow for the supported channel integrations.
The Webchat integration
The Messenger integration
The Alexa integration
The Assistant integration
Sure you can, you can make use of our API to do so.
Check out the API section for more details.