In some cases, you many need to set a question as 'required' to answer - it may be that one or two questions are crucial to your consultation outcome and without those answers your analysis would not be useful.
If you need to set a question as 'required':
1) Add your question (see this article if you need assistance in adding questions) or edit an existing question.
2) In the answer components section, select the option you wish to use - e.g. email address
3) Add in the accessibility details (if required for that type of answer component) and then, to make the question required to answer, check the box next to "Is the user required to respond?" as indicated in the screenshot below.
4) Save changes and you're done!
Pro tip: Try not to make too many questions 'required' to answer as this can be prohibitive for your respondents. They will not be able to submit their response if they have not completed all your required questions, so you may have an increased dropout rate if you make more questions required to answer than is absolutely necessary for your analysis.