Actually my friend bought me a mobile from UK , its SAMSUNG J3(2016). But now i now need to use VOLTE in India in Jio 4g network, which is not available in the foreign made by default. Which firmware i need to use? Also please tell me how to do this?
If you want to flash a new ROM then you should collect essential information from XDA forums about your device. Flashing a new ROM is a risky task so you must create a backup or something to fix your handset.
If you don't want to risk anything then use Jio4GVoice https://play.google.com/store/apps/details?id=com.jio.join&hl=en . You can Call, SMS, etc without a VoLTE enabled handset.
There are multiple variants of J3 (2016) on the market - the one designated for India is SM-J320F, so if that's the model you have on hand right now, flashing an Indian stock firmware from the linked page should make the phone behave exactly like it's purchased from India directly.
Do note that the one on sale officially in UK is SM-J320FN (mainly sold in Europe) which, despite the similarities, won't allow you to flash a J320F stock firmware on it directly.