Mac

To make a screenshot on a Mac, you have three different options:

Press "Command-Shift-3." The Mac will capture the entire screen and save the image on the desktop.
Press and hold "Command-Shift-4." Selection cross-hairs will appear. Drag the cursor across the screen to capture the desired portion.
Press and hold "Command-Shift-4", the cursor will change to a cross hair. Press the spacebar and your cursor will change to a camera. Click the application window you want captured.

Whichever method you use, your screenshot will be saved, typically either to the Desktop or the Downloads folder.

PC

Taking a screenshot on a PC is a more complex task depending on which version of Windows your machine has installed.

For a PC running Windows 8 or higher

To capture a screenshot, press Windows Key + Shift + S. This will bring up the Screenshot Tool and allow you to select the area of the screen you would like to be saved as a screenshot. After making your selection, the Snip tool will appear. From here, you can save your screenshot as an image file by pressing the Save Icon (which looks like a floppy disk).

For a PC running Windows 7 or Vista

Press PrtScn to copy the window into memory. Open Photoshop, or any image editor of your choice and start a new file. Paste the screenshot into the new file. Edit and save.

IOS

Press the Home button and the Sleep/Wake button simultaneously. Your screen will flash white. Your screenshot will be captured and saved to your Photos app.

If you phone uses Face ID and does not have a button, press the side button and the up volume button simultaneously.

iPhone with a home button:

iPhone with face recognition:

Android

Press the Volume Down button and the Power button together and hold for one to two seconds. Your screen will flash white and capture the entire screen. If that doesn't work, try pressing and holding the Home and the Power buttons. Your screenshot will be saved to your Gallery or Photos app. Some Android phones have different