That’s because the documents param is an xml and does not contain the actual csv itself. I’d recommend using create variables from CSV instead of Excel ETL. You need to get the Document Id of the csv from the documents xml and use it in the Upload CSV field as variable. 

1. I got the params as xml and used the document id and used it in find document step and saved the document.
2. Used the above saved document and used a create variables from csv step and has saved the output document. The Variable shows all the data that was there in the csv in a proper rows.row.row format .
3. I use this document in the Excel ETL Step in the Document Field. But the Document that I have used I understand it can’t be determined by the CLM if its a csv or docx file. To determine that I tried renaming the document by using the Rename Document Step but the Rename Document step says its not a valid document and the file extension can’t be set also. If i don’t use the rename document step and directly use the Excel ETL Step then the Step fails as throws an error “No valid Document Found”.
   Need better approach I Guys.

Did you try setting the Configuration Variable instead of configuration document? Btw, excel ETL supports only XML documents as configuration document, not CSV or docx. Also, it would be helpful if you could provide more context of what you’re trying to achieve from the ETL output