Hi Sumit -
You'll want to be a bit more specific. What data source in the cloud? As stated, your question is so general that any answer you get (like "You connect to data on the cloud like you would a regular data source") will either be incorrect or not useful
Maybe you can also tell us why you're asking this question - we can give you answer that "fits" you better in that case....
We have a salesforce datasource which is on cloud and we want to fetch the data from that datasource in tableau and generate the reports.
May be it can work as we do with the general datasources . But if anyone has used it earlier that would certainly help me to start the work.
There is a specific SaleForce connector that comes with Tableau. Just google "Tableau SalesForce connect" and you'll find everything you need