DNS translates human-friendly domain names into the destinations used by websites, email systems and other services. An A record usually points a hostname to an IPv4 address, while CNAME records create aliases to other hostnames.
What to consider
MX records direct email delivery. TXT records are widely used for domain verification and email authentication such as SPF, DKIM and DMARC.
Because DNS is shared by many services, changes should be planned carefully. Record the current values before migrations and understand TTL values so you know how long caches may retain older answers.