AAAA is a domain name record, that's in essence the IPv6 address of the server in which the domain is hosted. The IPv6 system was introduced to replace the present IPv4 system in which every single IP is comprised of 4 groups of decimal digits ranging from 1 to 255 e.g. 22.214.171.124. On the other hand, an IPv6 address has 8 groups of 4 hexadecimal digits - from 0 to 9 and from A to F. The main reason for this transformation is the considerably smaller amount of unique IPs which the existing system supports and the quick increase of gadgets which are connected to the Internet. An illustration of an IPv6 address would be 2101:1f34:32e2:2415:1365:4f2b:2553:1345. If you wish to direct a domain to a machine which uses this type of an address, you have to create an AAAA record for it, not the commonly used A record, that is an IPv4 address. Both records have the exact same function, but different notations are used, to distinguish the two forms of addresses.