What about Starhub?
Do they need to add or enable 4G HD Voice into our profile or account?
I don't see any VAS mentioning VoLTE, HD Voice that can be added in Starhub account system.
If your handset do have the icon and support VoLTE then enable to see if it works or not.
If it do not works you can contact Starhub to enable this features if your handset is capable else they would say handset is not applicable.
Note that VoLTE works on 4G/LTE network signal and not on 3G.
There is no need to enable the feature as it would be pre-set by Telco, where applicable.

