This page shows the public IP address your device uses to reach the internet. If your provider and network support IPv6, you will see your IPv6 address, otherwise your IPv4 address.
IPv4 addresses are 32 bits long and written as four numbers (e.g. 203.0.113.42). IPv6 addresses are 128 bits long and written as eight hexadecimal groups separated by colons (e.g. 2001:db8::1). IPv6 was introduced because the IPv4 address space is exhausted.