With any Wi-Fi calling-capable Android device, you can set your device to prefer wifi calling by: Apps icon > Settings > Advanced Calling; Tap Wi-Fi Calling; Tap When Roaming; Tap Prefer Wi-Fi; Now when making calls over Wi-Fi: Calls to US numbers are not billed (except for 411 or other premium calls).
Dec 02, 2019 10 best free calls apps for Android! - Android Authority Apr 08, 2020 How to Make Wi-Fi Calls on Android Smartphones
Make calls over the internet on Voice - Android - Google
20 Best Free Internet Phone Calls Apps - Lifewire Jul 03, 2020 Dingtone - WiFi Calling & Text on the App Store
How to Use WiFi Calling on Your iPhone - Techlicious
How to make free phone calls – even on your tablet