VoLTE not available on my xz premium but my operater did provided VoLTE for my number already

[Ken19981]

VoLTE not available on my xz premium but my operater did provided VoLTE for my number already but my handset not seem to have the button to just simply turn it on please add the button on to all sony Xperia handset this should be standard of all phones

[Uliwooly]

@Ken1998

This has been asked myriad times (you can do a quick search) if the phone its not locked to a carrier it's highly unlikely that it will work as is up to them, the carrier network, to enable this feature.