There are possibly two parts to this question.
​
If you are referring to the "mysupadupa.com" that appears in the URL, then yes you may purchase your own domain name and use that as the URL for your boutique instead.
​
More likely, you are referring to the "E-Commerce By SupaDupa - Create Your Own Online Store" tagline at the bottom of your pages. Please see this article for information on how to do that: How to remove Supadupa Logo - de-badge credit at the footer
​
​