Numbering submission

I am not exactly sure what you are trying to achieve. 

Do you want to check number of submissions of your form? You can check that on My Forms page of your account.

Or on submission page of your form. How to View Form Submissions

In case that you want to add custom Unique IDs to your form submissions, please check this guide:

https://www.jotform.com/help/79-How-to-Add-Custom-Unique-IDs-to-your-Form-Submissions 

In case that I did not understood your question correctly, please explain in more details what you are trying to achieve. 

Let us know if you need further assistance.