To take a screenshot on an Android device, you must:
- Press the Power/Lock + Volume Down buttons for a few seconds.
- On some devices, mainly those with older versions of Android or Samsung, those buttons may be Power/Lock + Home.
To check if the screenshot was taken correctly, go to the photo gallery and look for it in the "Screenshots" section. Whenever you take a screenshot, the device will emit a shutter sound; this will also help you to know if the screenshot was taken correctly.