It can be anything! An apex, subdomain, or even a URL.
Domain Name: www.my.happily.aiDomain Status: No Object Found>>> Last update of WHOIS database: 2024-09-22T12:34:19.102Z <<<
Domain Name: www.my.happily.ai
Domain Status: No Object Found
>>> Last update of WHOIS database: 2024-09-22T12:34:19.102Z <<<