The address in the box
Open what is my IP address. The large number is an IPv4 address, four groups separated by dots. That is the address most websites see. Copy it if a form or a support agent asks for your IP address.
Some networks also have an IPv6 address. It is longer and uses colons. It is listed under the main IP so you can inspect it. The headline stays the IP address people expect.
Public and private
A phone on home Wi-Fi often has a private address such as 192.168.1.20. That address never leaves the house. The public IP address is shared by the devices on that connection and is the one this site shows.
IP address and location
The number is not a house. IP address location shows the city and region registered to the network.