voLTE is usually driven by the network sim card in it, and if that network supports that feature and is available in the area your in.
Therefore it maybe beneficial to speak with your network customer service first @vignesh
Also to add there can be pitfalls when importing phones meant for another country as some features may not work as well.
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "