:-Check the following steps to save the battery in your phone
1.Let your screen turn off sooner. To reduce battery drain when you're not using your screen, set a shorter time before your screen turns off.
2.Reduce screen brightness. To save battery, lower your screen's brightness.
3.Have screen brightness change automatically.
4.Turn off live wallpapers.
5. Turn off apps when not in use.
6. Turn off internet when not in use.
7. Turn off background data of your phone.
8. Switch off Wifi, Bluetooth, NFC and Locating when not in use.
You can watch this video link for more details:
You can check the complete specs of this phone:
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.
1. Go to Settings > Call Settings (Sim and Network)
2. Tap Cellular networks > Enable Voice over LTE On/ Off.
Alternatively, you can simply dial *#*#4636#*#*
Choose Phone information.
Click " Phone Information" and Toggle VOLTE Provisioned.
Restart the phone and you are done.
You can find full specifications here: Samsung Galaxy J8 2018
Open a chat with a contact you want to call.
Alternatively, you can use Google Hangouts.
Google's own video and messaging app are one of the most popular ways to make voice and video calls from your Android phone, and that's not just because the app usually comes pre-installed. ... You can chat one-on-one, or add more participants (up to 10), using your phone's front or rear camera.
The alternate application includes Whatsapp, Duo, Messenger e.t.c. which you can download from Play Store.
You can see complete specifications here: Samsung Galaxy J8 2018