How to add an auto numbering value to a form?

IS there an auto mumbering widget. (eq: next form is 2, then 3, etc)

Yes, you could use the Unique ID widget: http://widgets.jotform.com/widget/autoincrement. 

This guide will help you to add the widget to your form: http://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form. 

Here is also a guide about it: http://www.jotform.com/help/79-Add-Custom-Unique-IDs-to-your-Form-Submissions. 

Hope this helps.