Since we only provide hosting services, your DNS entries need to be managed elsewhere. Chances are, they're already managed at your registrar level (e.g., GoDaddy, Namecheap), but you can also use a specialized service (e.g., Cloudflare, Amazon Route 53).
Because we do not handle your domain's DNS entries, you don't need to use our nameservers to use our services. However, your domain names still need to point to the hostname of your server using A records.
Your server has a unique IP address and a unique hostname (e.g., "your-server.mach4.io"), both shown in Sites and Databases > Domains.