Apple Watch Series 3 allows you to make and receive calls on your watch. Not only that you can live stream the music also. Watch this video to know more.
Yes, Apple watch series 3 works well with Apple iPhone 6. Check this video explaining how to pair your Apple watch with iPhone 6.
Yes. Currently, Jio and Airtel networks are supported on Apple Watch series 3 GPS + Cellular model. Your number will remain the same.