@aldercar, please be informed that I have split your issue so we can have a single post for a single issue and it’s easy for the community to search for related issues when needed. As confirmed by @wroos, changing the question type from one question type to another is impossible through the formbuilder. You could, however, download your form as XLSForm and then change the question type as needed.
But, we always advise you to try this out on a dummy project first so that you will know hoe the data is structured later on (when the project is complete).
