Hey,
** CNAME Records are used for identify multiple domain names that point to the same IP address.**
A Canonical Name record (abbreviated as CNAMErecord) is a type of resource record in the Domain Name System (DNS) used to specify that a domain name is an alias for another domain, which is the "canonical" domain.
For SEO point of view:
Every website needs a ‘canonical’ or definitive web address of the site.
Generally, this is the non-www (bare domain name without the “www” in front).
Search engines view both the “www.site.com” and “site.com” as two different addresses so it's important to point the www version to the canonical name (or the non-www to the www).
