How do I take a screenshot?

Windows :

How do I take a screenshot?

Press PrtScn = Windows takes a picture of the whole screen and puts it in the pasteboard.

How can I paste it into a document or image?

Open microsoft office or paint and hold Ctrl and press V = Windows pastes the screenshot into the program

Mac (OS X)

How do I take a screenshot?

Press ⌘ command along with ⇧ and press #3 = Mac OS X takes a picture of the whole screen and saves it as a file on the desktop.

How can I paste it into a document or image?

Press and hold ⌘ command along with V = Mac OS X pastes the screenshot (which is in the pasteboard) into a document or image you are editing.

screen movie / screen recording in MacOs Mojave

In macOS Mojave, press Shift-Command (⌘)-5 on your keyboard to see all the controls you need to record video and capture still images from your screen.