How can I make a 3% charge optional and have it automatically calculate

I would like to ask people to add a 3% fee to their charge and have the 3% charge automatically calculate.  Can that be done on this same form?  Please provide specific instructions.

There is no direct way to do this. We will get back to you via your original thread:

https://www.jotform.com/answers/1055820

Thank you.