Pointing a name at an address.
THE A RECORD
Maps a name to an IPv4 address. The fundamental record of the web.
yourdomain.com with the address of your server.
WHAT YOU NEED
One for the bare domain One for www, or a CNAME One for each subdomain not covered by a wildcard
FINDING YOUR ADDRESS
Shown in cPanel on the right-hand statistics panel, as the shared or dedicated address.
Use that, not one you remember from elsewhere.
THE AAAA RECORD
The same for IPv6. Optional on most hosting.
If you create one, ensure it points somewhere that actually serves your site. An AAAA record pointing at nothing makes the site unreachable for IPv6-capable visitors while appearing fine to you.
That is a genuinely confusing failure.
MULTIPLE A RECORDS
Possible, and it distributes queries between addresses. Not something you need on shared hosting.
CHANGING THE ADDRESS
After a server move, every A record must be updated.
Missing one leaves a subdomain pointing at the old server.