How to set registration numbers to tickets sold through our form

we have an event where people purchase tickets.  We want to issue each ticket buyer a 4 digit registration number.

Can this be done on Jotform?

Based on your description, it sounds like you would like to send unique 4-character-long IDs to your buyers. Yes, this can be done with JotForm by using our Unique ID widget.

Please see the following guide for more details:

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

If you need any further assistance, or if you were looking for something else instead, please let us know and we'll gladly help. Thank you.