
That 2 iPhones are connected to the internet through the Personal Hotspot of another iOS device.
More info about Hotspot:
How to set up a Personal Hotspot on your iPhone or iPad
How to set up a Personal Hotspot on your iPhone or iPad - Apple Support
Share your internet connection from iPhone
Share your internet connection from iPhone - Apple Support (IN)
For Wi-Fi connection, see the following Apple articles:
Connect to Wi-Fi on your iPhone, iPad, or iPod touch
Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network
If your iPhone or iPad won't connect to a Wi-Fi network - Apple Support
Turn Hotspot -> OFF.