My registrar is stipulating the DNS HOST field must be a hostname not an IP address.
What is the host name for pointing to pages, is it the same as for subdomains??
It’s also asking for a NAME (ie NAME.mydomain.com) what is the name here, “dns”???
what are you trying to achieve?
@datlinux Hi and welcome to our community 
Can you share which domain registrar you are using?
For the root domain, an A record is required. Sub domains may use a CNAME/ALIAS record. GitLab Pages custom domains | GitLab
The instructions are given in the Pages settings overview too, next to the documentation steps.
My registrar is stipulating the DNS HOST field must be a hostname not an IP address.
If that’s Namecheap/Godaddy/etc., you can ignore that warning. An IPv4 address works very well as A record / DNS Host entry. I’m using Namecheap, next to many years maintaining DNS servers in my previous jobs. Example for everyonecancontribute.com 
In addition to adding the A/CNAME/ALIAS record, you also need the TXT record with the verification code.