All questions must have unique XML names. We suggest taking the first Letter of each work in the section title you are creating questions to add at the beginning of the XML for example.
If you are working on a Section called "Applicant Information" and the Question is First Name the best practice xml for that question would be a First Name.
If there is multiples of the same question you can add a 1,2,3 etc at the end of the XML name.