I need and excel form for cvs

I am doing some internet marketing.   I have a list with all my potential customers email addresses.

The form must be a CVS form that is compatible to send through my autoresponder.  

The process to make that form compatible is to go to the File and click on Save as. 

There is supposed to be an option to click on to make that form compatible to CVS.

I do not show that option.

How do I show that option?