How to making simple submission number?

Can you help me how to making simple auto subission number field for our form? For ex. 001, 002, 003...

Thanks.

You can add Unique ID widget to your form so that you can generate an auto-incremented value for each submission. This widget will not be displayed on your JotForm when viewed normally.

http://widgets.jotform.com/widget/autoincrement

Please refer to the guide below that can help you with using this widget.

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

Hope this information helps!