There are multiple ways to take a screenshot. Here are the most common ways for Windows and MacOS.
The easiest way to take a screenshot is with the Window Snipping Tool:
Simply press Windows logo key + Shift + S on your keyboard for a static image snip.
When the screenshot is taken, it's automatically copied to the Snipping Tool window where you can edit and save your file.
The easiest way on MacOS to take a fullscreen screenshot is by pressing CMD + SHIFT + 3 on your keyboard. The file is automatically saved to your desktop.