How to let users to add fields dynamically

It would be great idea to introduce a feature of dynamically repeating a section, for example add more authors....

Such a feature is available on some other form builder sites. e.g.

https://www.cognitoforms.com/features

Thank you for your suggestion. If I understand your question correctly, you want to let your users add fields dynamically. It is already possible with the configurable list widget and the Infinite List widget with JotForm. You can also customize the CSS as you see below:

If you have any question or issues, please do not hesitate contacting us. We will be glad to assist you.