I need to allow the users repeat some of the form fields(or form groups) in the survey forms. There should be a + or - button next to the field that if the user clicks on +, then a new field is created.
Example: https://www.rhyzz.com/repeatable-fields.html
I would be surprised to know if Qualtrics doesn't have this feature.
I google for this but no success.
You can't create new fields (choices, answers, variables, etc.) on the fly in Qualtrics. A field has to be defined in the survey for it be be saved in the response data.
You could write a JavaScript to show and hide fields to give the appearance of adding and removing fields, but you would have to define the maximum number of fields in the survey beforehand.