iOS WiFi Calling 1. Open Settings 2. Tap Cellular 3. Tap Wi-Fi Calling 4. Turn on "Wi-Fi Calling on This iPhone" 5. If prompted, confirm your emergency address with your carrier Android WiFi Calling (steps vary slightly by phone) 1. Open Settings 2. Tap Network & Internet (or Connections) 3. Tap Wi-Fi Calling 4. Turn it on 5. If given the option, set network preference to "Wi-Fi preferred" for the best results indoors iOS FaceTime Audio (works over WiFi with no cell signal, Apple devices only) 1. Open the FaceTime app, or open a contact in Phone/Contacts 2. Tap the phone icon next to their name (not the video icon) for an audio-only call 3. With their number saved, you can also say "FaceTime audio [name]" to Siri