What are DNS records?
There are different types of DNS records, each with a specific function:
Record A : used to point a domain sitename.it to the web server on which the site resides, i.e. to create the connection between the domain and the IP address.
AAAA Record: Used to create a link between a domain and an IPv6 address. It works very similarly to the A record but is linked to an IPv6.
CNAME Record : Used to create aliases of an A or AAAA record and reach the same IP address. Used to associate a subdomain blog.sitename.it with the main domain sitename.it

MX Record : Used to determine which servers are authoritative for delivering mail for the domain namesite.it and must necessarily point to a hostname. Usually, the prefix is always and the pointing will identify the @namesite.it mailboxes
TXT Record – Typically used to associate SPF records with the domain name to improve email deliverability and protect against potential spam.