I am creating a web page in asp.net C# where users enter their information like employee\_id, name, skill\_name, skill\_category, skill\_proficiency etc.

When they click the "submit" button, I want an Excel file (.xls) to be generated on the server where all data gets stored. As users continue to enter data, the Excel file must be populated. 

I know using a DB here is a must, but I have been told to strictly use Excel file as the scope of project is very small. 

Any starting point to help will be appreciated.