How does Apache webserver is able to detect CNAME

I was quite curious how does Apache web server can detect a subdomain even when all the subdomains point to same IP address, since my understanding is that an IP address that cannot have a subdomain, and every domain name ultimately resolve to an IP address. Example: example1.domain.com resolves to => 192.24.17.65 take you to => example1 webpage example2.domain.com resolves to => 192.24.17.65 take you to => example2 webpage