During installation of CentOS 7 what to choose for host name

I'm trying to install CentOS 7 server. During the installation what to choose for the host name? Is "server.mydomain.tld" good or do I need to choose only "server"?

The official CentOS documentation says the hostname should be the FQDN.

HOSTNAME=<value>, where <value> should be the Fully Qualified Domain Name (FQDN), such as hostname.example.com, but can be whatever hostname is necessary.

During the CentOS 7 installation in the INSTALLATION SUMMARY screen of the CentOS 7 installer, click on the NETWORK & HOSTNAME label and type your system FQDN in the Hostname field. FQDN is combination of hostname+domain-name. For example, if your hostname is server and your domain-name is mydomain.com, then your FQDN is server.mydomain.com

To change the hostname in CentOS 7, follow the instructions in RHEL / Centos Linux 7: Change and Set Hostname Command.