In the past, to take a screenshot on an Android phone, you had to install the tools for Android developers. Nowadays you can take screenshots with a few button presses on phones running Android 4.0 or later.
On most Android phones, you can take a screenshot by pressing and holding the power and volume down buttons at the same time. Press and hold these buttons until your screen flashes. Also read: Samsung Galaxy S6 - The rumors and speculations.
However, the process is different on some phones. For example, on Samsung's Galaxy phones - and certain third-party phones that have a home button - you'll need to press and hold the power button and the home button until the screen flashes, as noted above. If your Android phone has a home button, try this power button and home button combination.
To view your screenshot, go to the Gallery app and search for the Screenshot album. Tap it to open the album and then tap the screenshot you took to view it. Tap the Share button - a sideways V-shape connecting three dots - to reveal options such as sharing via SMS or email.