Is it possible to generate a registration number to an individual once they have completed my form?

I am registering athletes and need them to have a registration number once they have completed their form and paid their registration fee. Is there a widget for this or a way to do this?

You can use the Unique ID widget. This widget allows you to uniquely identify each form submission with a customized, unique and sequential identifier. Here's a guide: How-to-Add-Custom-Unique-IDs-to-your-Form-Submissions.

You can also use the Random Value Generator widget. Here's a guide on How-to-Add-a-Widget-to-your-Form.

Hope that helps. Thank you.