What's the diference between ANAME and A?

If you don't understand the difference between an A record and a CNAME record, don't worry about it and continue using A(AAA) records. You aren't missing out on anything. There's nothing terribly revolutionary about them, it's mostly marketing hype.

ANAME is a custom record type which emulates the behavior of a CNAME record, but can be used at the apex of the domain. This is desirable for some because CNAME records cannot be used at the apex of a domain. It doesn't break the existing standards because the server software "clones" the target instead of using an actual CNAME.

It must be emphasized that ANAME (and similar features advertised by other companies, such as ALIAS) are not part of the DNS standards. As such, do not expect the aliasing to be intact if you switch DNS hosting companies.

Just to spell out more clearly what the previous answer says: the difference between A/AAAA and ANAME is that A and AAAA are DNS record types, while ANAME is a service offered by some DNS hosting providers. They implement that service by creating actual DNS records (A, AAAA and others) on the fly. It can be a convenient service, but it doesn't mean that you can find ANAME anywhere in the official list of DNS record types.