Configure your power saving modes

Samsung’s Ultra Power Saving Mode  on the S6/S6 Edge can stretch a tiny bit of battery life into more than a day of use. The phone won’t be as much fun to use, but you’ll be able to take calls, send messages, and use a select few apps.
Ultra Power Saving Mode switches the device to a simplified black and white interface and disables most background services. Before you find yourself turning it on with a nearly-dead battery, you should fire it up while your battery is full and get things organized.

There’s a notification toggle to activate Ultra Power Saving Mode when your battery gets really low, but it can also be accessed from the battery settings menu.
In Ultra Power Saving Mode you can select a few apps to have as shortcuts on the home screen. There aren’t many, but you can choose from the stock browser, Google+, messaging, and a few others.

There’s also a regular power saving mode that’s a little less extreme.
This setting reduces the screen brightness, down-clocks the processor, reduces the display’s refresh rate, and shuts off vibration. This mode can be configured to switch on automatically when you reach a certain battery level between 50% and 5%. It’s a good idea to set this up. You’ll find it in Settings > Battery > Power saving mode.