You might want to take screenshots of a funny scene, or in some cases, screenshots might be needed to resolve an issue. You can take screenshots by doing the following.

Android
-Press and hold the Home button and the Power button at the same time.
-Press and hold the Power button and the Lower Volume button at the same time.

※ Important: For Android OS, please note that the above may not be applicable as the method for taking screenshots may vary depending on the device.