Anycast is a network addressing and routing methodology in which a single IP address is shared by devices (generally servers) in multiple locations
Routers direct packets addressed to this destination to the location nearest the sender, using their normal decision-making algorithms, typically the lowest number of BGP network hops.
IPv4 → implemented through BGP, where multiple hosts (usually in different geographic areas) are given the same anycast IP address and they all announce it to their BGP table.
IPv6 → Explicitly supported
https://www.cloudflare.com/learning/cdn/glossary/anycast-network/