From the Home screen, navigate: Apps icon > Settings > Advanced Calling.
If unavailable, navigate: Apps icon > Settings > More > Advanced Calling.
For Oreo OS, navigate: Apps icon > Settings > Network & Internet > Mobile network > Advanced > Advanced Calling.
For Samsung devices, navigate: Apps > Settings > Connections.
Tap Wi-Fi Calling.
Tap Update Current Emergency Address.
Edit the address if needed then tap SAVE.
This info gets transmitted to the emergency dispatcher for all 911 calls made over a Wi-Fi network. If address validation fails you are prompted to enter a new address until a valid address is entered.