How do I take a screenshot on Linux?
On most modern desktop environments (like GNOME or KDE Plasma):
press PrtScn
This will typically capture the entire screen and save it to your Pictures folder, or open a screenshot utility dialog.
How do I capture the active window?
press Alt + PrtScn
How do I capture a specific area?
press Shift + PrtScn
Your cursor turns into a crosshair allowing you to select an area.