VoLTE or Voice Over 4G LTE network offers superior voice quality as compared to VoWiFi. You can still browse while being on a call. It has multitasking capabilities to switch between apps, such as video calling, multimedia file sharing, images and phone calls simultaneously at the fastest speed.
VoWiFi uses the WiFi network to make calls in HD. VoWiFi improves call reliability indoors, regardless of your mobile signal strength.