You can also transfer your domain to Smarthost and make payments for hosting and domain through our Customer Panel. In case of that, you will need AUTHINFO code, which you can obtain from your domain register. If you have it, login to our Customer Panel (not cPanel) and go to Domains → Domain transfer. Fill the form using AUTHINFO code.
If you want to create subdomain, e.g. subdomain.customer-domain.eu you should add it through cPanel → Subdomains.