Yes, you can register a new domain name for your store – through us or through a specialist domain provider – and point it to your new website.
If you register a domain name through us, you can select this on checkout when you sign up:

If you have already purchased a domain from a domain provider or will be purchasing one from another provider prior to your website going live, you can choose the third option “I already own a domain with another provider. I will point my domain nameservers to my new online store”.