What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I believe you can use Configurable List widget for your form.
It allows a user to add another set of fields when they click the + button, which can also be modified. Here's a sample where you can see the configurable list in action: https://form.jotform.com/60408152193955
You can also clone the form by following this guide: How to Clone an Existing Form from a URL