Hi Jean,
Unfortunately there isn't a way to mass apply the 'Send Email Notification' processing step to every form in Eloqua. If you don't feel that you have a good accounting of the live forms and/or do not want to add this processing step to each form individually, my recommendation for the next best thing would be to set up a form report in Insight that will tell you the # of forms submitted by Form name and set up that report as a subscription that is sent to you at a high frequency.
Hope this helps!
E