If you want to add selected fields to show based on previous answers, you can use logic and add more fields in the logic settings.
Let's see how to do this:
We have a form with a single-choice question, and 3 other fields (name, email, and address).
We want to show the name and email if the answer is option 1
and show the name and address if the answer is option 2.
Save the form and go to the "Logic & Calculator" tab.
Set the logic using the "+Add More Fields" option.