A public IP address is used on the internet-facing path of a connection. An external service can report the source address it sees for a request. That address may belong to a router, provider, proxy or VPN exit rather than uniquely identifying the device in your hand.
A practical example
Your laptop’s Wi-Fi settings and a browser IP checker may display different addresses. The first may describe the local network interface, while the second describes the request as seen outside that network. Compare like with like before treating the difference as an error.
What to check
Use the same external checker before and after changing a connection. Record the time, network, address family and selected VPN option where relevant. If you need to share a result with support, include only the information needed to investigate the task; do not publish a full connection history.
What it does not tell you
An IP address is not an exact home address or a complete identity. A changed browser IP does not prove coverage for every app, and a location label supplied by a database is not a precise device-location test. The public-IP guide explains how to interpret a before-and-after check.
Read the technical reference for the underlying definition. For a connection that is failing now, use the troubleshooting guide. To choose an app, follow the VPN selection worksheet.