A type A record resolves a name of the type xxxx.domain.tld to an IP address.
In an Active Directory environment, computers register with the DNS server when they have their IP address given by the DHCP service.
In business, this type of registration is often used for setting up web services.
If you decide to set up GLPI, you will probably need to add a record of this type glpi.domain.tld.
Type A record = IPv4 and AAAA = IPv6