On most Android devices the easiest way to take a screenshot is to simultaneously press and hold down the power button and volume-down button.
The screen will flash, and a notification will pop up pointing you to the new image in your gallery. Some devices allow you to edit it there and then, but if not just dive into your phone gallery where you can deal with it there.
If this doesn't work, try holding down the physical home button and volume-down simultaneously.
Here are some alternative methods for taking a screenshot on Android:
Ask Google Assistant to take a screenshot
If you have the Google Assistant configured on your device, ensure it is set up to wake with the "Okay Google" command from any screen.
You can set this up by launching the Google Home app, clicking the Account icon at the bottom right, then choosing Settings. Select the Assistant tab then choose your phone under Assistant devices. Ensure 'Access with Voice Match' is enabled.
Now at any point while using your phone you can simply say: "Okay Google, take a screenshot."
Use screenshot gestures
Some Android phones allow you to trigger a screenshot with a palm-swipe gesture, though you'll need to enable this first.
You'll find the toggle in Settings > Advanced Features > Palm Swipe to capture.
Samsung phones have some additional screenshotting options such as Smart Select and Scroll Capture, which we outline here.
On Huawei phones, you can also screenshot by performing a double knock with a knuckle anywhere on the screen. However, there comes a point where it starts to become a gimmick rather than your go-to method. (Saying that, knocking twice with two knuckles starts and stops screen recording, which can be handy.)
Check for screenshot options elsewhere in the UI
Sometimes you'll find a screenshot button in the phone or tablet's user interface. Common places for this include the power options menu (when you press the power button), the drop-down notification bar, and in Quick Ball if your device supports such a feature.
On Android 9 Pie and later, there is an option to trigger a screenshot when you press and hold the power button, however this is only available on devices which are running close to 'stock' Android.
We couldn't find any similar option on Samsung's One UI, for example.
Finally, if you're looking for how to screenshot on an iPhone (if so, what are you doing here?!), we've got that covered separately.
How to Record the Screen in Android
Your phone might be able to do this natively, or there may be an app pre-installed on your phone that can record the screen - check before you download another one - but if not simply launch Google Play and search for Screen Recorder.
The app we have used in the past is now called the Riv Screen Recorder. It's free to install, but there are now many other options too.
Simply install the app, click Open, and press the Start Recording button to begin your screencast. Press Stop Recording when you have finished, and the file will appear in the main window with playback, sharing and delete options.
Ideally, the recording overlay won't show in the video, but if it does, look for an option to hide this in the recording app's settings.
You can use the video editor on your phone (part of the default Gallery app if nowhere else) to trim the start and end points if you need to.
Another popular option is XRecorder, which essentially does the same job.