Public address, private address
The number above is the public address of the network you are using. Every site you open can see it, because your traffic has to say where the reply should go. Devices inside your home usually use private addresses such as 192.168.0.20 or 10.0.0.5. Those never travel onto the public internet. Your router, or your ISP, presents one public address for many devices. That is why a phone and a laptop on the same Wi-Fi often show the same result here, and why the result changes when you switch to mobile data.
The place name is a guess attached to the network, not a reading from your phone's GPS. This page does not request location permission. Coordinates often point at an ISP facility, a city centre, or the exit of a VPN, and they can be wrong by many miles. Do not treat them as a home address.
IPv4 and IPv6
IPv4 addresses look like 203.0.113.10. There are not enough of them, so many households share one. IPv6 addresses are much longer and are written with colons. Some networks offer both. If the IPv6 line says none was offered, this browser reached the lookup over IPv4 only. A VPN or a mobile carrier can hide IPv6 even when your home connection has it.
Why the address changes
Home ISPs often rotate the public address. A VPN replaces it with the provider's exit address, which is the entire point of the VPN. A corporate network, a university, or a café will show the building's address rather than anything personal to your laptop. Privacy extensions on IPv6 can also change the address a site sees without you doing anything.
Address allocations are coordinated by IANA and handed to regional registries, who assign blocks to networks. The ISP name on this page comes from that kind of registry data, matched to the address by a lookup service. It can lag behind a reallocation.