This video will show you how to share wifi from iPhone to iPhone. Make sure that your device, the one sharing the password is unlocked and connected to the internet.
1. To do that, open Settings.
2. Tap Cellular.
3. Turn on Cellular Data.
4. Now Turn on Personal Hotspot and set up it.
5. Turn on Allow Others to Join.
6. Enter Wifi password.
7. On the second iPhone, turn on Wi-Fi and then connect the Wi-Fi network.