Does Iphone 6 support VoLTE

Yes,

Audio Calling

• FaceTime audio
• iPhone 6 to any FaceTime audio-enabled device over Wi‑Fi or cellular
• Voice over LTE (VoLTE)
• Wi‑Fi calling

1. FaceTime calling requires a FaceTime-enabled device for the caller and recipient and a Wi‑Fi connection. Availability over a cellular network depends on carrier policies; data charges may apply.
2. Data plan required. LTE, VoLTE, and Wi-Fi calling are available in select markets and through select carriers. Speeds are based on theoretical throughput and vary based on site conditions. For details on LTE support, contact your carrier and see www.apple.com/iphone/LTE