To take a screenshot on a computer, the method depends on the operating system: For Windows:

• Press the Windows logo key + PrtScr (Print Screen) key together to capture the entire screen. The screenshot is saved automatically in the "Screenshots" folder within the Pictures folder. It is also copied to the clipboard so it can be pasted into an image editor or document.
• Press just the PrtScr key to copy the entire screen image to the clipboard, which you can then paste into an app.
• Press Alt + PrtScr to capture only the active window.
• Use the Snipping Tool or Snip & Sketch tool (Windows logo key + Shift + S) to capture a customized portion or window of the screen.
• Screenshots can be pasted into apps like Paint using Ctrl + V for further editing or saving.

For macOS:

• Press Shift + Command + 3 to capture the entire screen. The screenshot will save to the desktop.
• Press Shift + Command + 4 to capture a portion of the screen by dragging to select the area.
• Press Shift + Command + 4 then Space bar to capture a specific window.
• Screenshots may show a thumbnail preview to edit or will save automatically to the desktop.

This covers the common ways to take screenshots on computers using Windows and Mac keyboards. Let me know if there is a specific computer or detail needed!