This answer explains what an A record is and how it can be used.
An A record (or 'address record') specifies which IP is assigned to a particular domain. This entry doesn’t necessarily have to be made - a domain can for example be used only for mail services – so an A record for this domain is not necessary.
Alternatively, more than one record can be entered for each domain. In this case, a new record is returned for each query. This is particularly important for large scalable systems.
If you wish to change the A record on your domain name please see the following guide:
How do I point my domain name to an IP address?