how to export webapp created in dataiku tshirt?
There are no specific features in Dataiku to export a webapp.
Generally speaking, you can simply copy the code of your webapp and run it outside of Dataiku.
You will need to setup the dataiku libraries for working outside of DSS. Please see https://doc.dataiku.com/dss/latest/python-api/outside-usage.html and https://doc.dataiku.com/dss/latest/R-api/outside-usage.html for more details)