Your license will be set for this URL. For example, www.yourStore.com
According to the terms of the nopCommerce license, without purchasing the Copyright removal key:
Upon purchase of a "copyright removal key" you are permitted to remove the "Powered by nopCommerce" statement.
According to The World Intellectual Property Organization Copyright Treaty, The Digital Millennium Copyright Act (the USA), and official Directive of the European Union, site pages or an entire site which violates authors’ rights might be removed from Google search results and from other search engines if an author whose rights were violated makes such a request.
Copyright infringement is illegal - please be advised.
A wildcard copyright removal key is for multiple sites on a SINGLE domain. If you purchase such key for domain www.yourDomain.com, then you can remove "powered by nopCommerce" on the following sites as well - subdomain1.yourDomain.com, subdomain2.yourDomain.com, www.yourDomain.com/site3, www.yourDomain.com/site4.
A server copyright removal key is for one IP address. If you purchase such key for IP address (e.g. 126.96.36.1993), then you can remove "powered by nopCommerce" on all sites which could be accessed using this IP address. But it's limited to 100 sites per key (for example, if you have 200 sites, then you have to buy two server copyright removal keys). Please note that it's not allowed to purchase this key for IP addresses of hosting companies (e.g. Windows Azure, AWS, CloudFlare, etc).