Hi Shruthi,
Using Excel (or csv) as a tool to create Entities is not possible. You can create pretty much everything you want using the Platform SDK.
https://www.mendix.com/blog/presenting-the-mendix-platform-sdk/
If you are handy with Javascript & Typscript, you could extend the creation of objects with your own code, like using an external source to create an entity.
Cheers,
John
You can import from an XSD. So if you create an Excel macro that creates an XSD file based on you Excel you could use that.