WiFi calling in Android app

I have read it is possible to use wifi calling when accessing FreeConferenceCall via the Android app, but I cannot find a setting or other way to do that. Ideas?


To dial into a conference call using WiFi through the mobile application, you either click Join or Host. Once done you will then be asked: “How Do You Want to Call”. You will then choose “Call in Using WiFi or Data”. Thank you.