Somelse asked about what is DNS, but how are there multiple DNS server. You can buy a domain from cloudflare like say example.org, but how does clouflare get to claim that domain as it’s own, and how can there be DNS outages when there are multiple DNS servers? Is there a DNS authority? And does every government have there own DNS servers that point to the main ones?
All domain names are allocated by IANA. They sell IP addresses and domains in bulk to resellers, you buy it from them.