Switch to Save Battery

[vijju786]

There should be easy switch icon or button where if I'm running out of battery ..I should have a button or icon to switch to calls only option and my battery extends and I can stay connected in emergencies.. 

[AbhishekPuri]

yes, turn on power saving mode.
go to device setting > battery & device care >click on battery option > power saving mode > turn on all options > than turn on power saving mode. or scroll down notification panel > click on power saving mode and turn on all options.

[yadavmanish]

see notification panel