If you share a form with another user they will be able to view all submissions. There is no way to restrict access such that they are only able to view a single response.
I mean I only want this person to see the one form and its submissions. How is this done? Do they need to create their own adobe account based on the email address I shared the form with?
Thanks for clarifying. Please refer to the following article:
The person you share the form with needs to have a FormsCentral account (it can be a free account) associated with the email address that you shared the form with.