A CNAME record points one domain name to another domain name, not an IP address. It's a DNS alias—useful when you want multiple domains to resolve to the same destination without managing separate A records everywhere.
Common use: you register example.com but want www.example.com, blog.example.com, and shop.example.com all pointing to the same web server or CDN endpoint. Instead of four separate A records, you create CNAMEs for the subdomains pointing to one canonical name.
CNAMEs can't exist at a zone apex (the bare domain itself)—only on subdomains. If you need the root to alias elsewhere, use ANAME or ALIAS (nonstandard, registrar-dependent) or just point the A record directly.
Why it matters here: if you're running content on a CDN, bulletproof host, or reverse proxy, CNAMEs let you decouple your public domain from your actual hosting infrastructure. Change hosts without touching the domain registration. Also useful for anonymous setups—your registrant info stays clean while your CNAME infrastructure handles the operational layer.