On you device home page, proceed to Settings and select Wi-Fi (should be just below Airplane Mode).Select the information icon to the right of the connected network. It's the lowercase ( i ) in the circle. The title labeled IP Address would be your local IP address for your iPhone.
Also, if you use our Smart Family app, you can track the location of the other lines on your account. You can learn more about Smart Family and the many benefits of it here: https://www.verizon.com/solutions-and-services/verizon-smart-family/
Let us know if you have any additional questions!