This document describes how to check your iOS device's IP address.
On the home screen, tap Settings.
Select WiFi to open a list of currently available wireless networks.
Locate the wireless network to which you are currently connected in the list, then tap on the blue circle with an i that appears to the right of the network name.
The IP Address field should be the first field listed under the IPv4 section (on some devices/networks, this may be IPv6).