See the screenshot for your specific registrar below. If we don't have your registrar listed, you can look for similar records with your registrar. Specifically the "A" (Host) records & "CNAME" (Alias) records in the DNS Settings.
GoDaddy
1. "A" Record:
2 "CNAME / Alias":
Domain.com
1. "A" Record:
2 "CNAME / Alias":