Capturing screenshots on the Mac OS is quite easy. You’ll just have to learn the commands. So, without further ado, here are the keyboard shortcuts to get you going.
How to capture an active Window
Command + Shift + 4
To capture an active Window, use the keyboard by holding the Command and Shift keys, and then pressing the number 4. You will see a crosshair with the screen axis numbers next to it. Press Spacebar to select the entire active screen. Click the mouse or the touchpad to capture the screen. If you want to just capture a small section of the active Window, hold and drag the mouse or touchpad, when you see the crosshair with the screen axis numbers when prompted. The screenshot will be automatically added to the desktop.
How to capture an entire screen
Command + Shift + 3
To capture the entire desktop screen, use the keyboard by holding the Command and Shift keys, and pressing the number 3. The screenshot will be automatically added to the desktop.