@rahul_oberoi Adding a dropdown to an Excel file (.xlsx) is no problem, but your question relates to a CSV file. Such a file contains text only. Bits and pieces separated by commas. When you open such a file in Excel, all the pieces get placed on the Excel grid. You could then add the dropdown, but if you save the file as a CSV, all that functionality is removed and you end up with a text file again where the content of individual cells are stringed together and separated by commas.