When you don't use your iPad, it enters standby mode. Although standby mode doesn't use a lot of battery power, it still wastes some energy. If you're running low on battery life, you should shut down the iPad completely when you are not using it to save the remaining battery charge. Shutting down your iPad is straightforward; you can turn it on again at any time, provided you have some battery life left.
Locate the "Sleep/Wake" button on the top of the iPad. It's a small, black button.
Press and hold the "Sleep/Wake" button until you see a "Slide to power off" screen.
Slide the slider to the right to shut down the iPad.
Press the "Sleep/Wake" button again to turn on the iPad. The Apple logo appears on its screen while it is starting up.