You don't need to enable VoLTE. Insert the Jio (VoLTE enabled) in any slot. By default VoLTE will be active. If it is not, you can change the network preferences from Network option in settings.
To make video call from Xiaomi Redmi Y1 follow the steps below:
1. First open the dialer app
2. Then Dial the number in that app.
3. When you will type a number in the dialer app you will see a option showing on the top (Make Video call)
4. Tap on that option and enjoy the video call.You can also check this video for much better reference.
I will recommend you Realme 1 which offers great processor with better performance. It also has more storage capacity and face unlock.
You can also check the complete comparison here:
Check the Best phones under 10,000 : Best phones under 10K
In my opinion Xiaomi Redmi Y1 is best in specifications and overall it has powerful performance.
Check the link hereXiaomi Redmi Y1 vs Xiaomi Redmi 4 16GB
Xiaomi Redmi Y1 Lite vs Xiaomi Redmi Y1
Both the phones have their pros and cons,lets analyze:-
Advantages of Xiaomi Redmi Y1
1.Octa Core CPU:-More cores result in better parallelism, meaning more tasks can be processed in parallel without slowing down the User Interface.
2.More RAM:-More RAM means more applications can run at the same time, which makes the device faster.
3.More Storage Capacity:-More memory allows you to store more songs, videos, photos and install more applications.
4.Has Fingerprint Sensor:-Fingerprint sensor support allows you to quickly unlock your device using your fingerprint.
Verdict - In my opinion, Xiaomi Redmi Y1 is better overall performance and price
You can also compare these devices on 91mobiles