When you "copy" something to your clipboard, it is temporarily stored in the computer's memory. The clipboard is a virtual space where data is held temporarily while you move data from one place to another. Once you "paste" the copied material, it moves from the clipboard to the active window or application.
So, if you copy something to your clipboard from a website, for example, and then open a document in Word and paste the copied content, it will paste into the Word document. If you copy something else before pasting the first item, the new content will overwrite the previous content in the clipboard. However, if you do not paste the copied content before copying something new, then the original content will remain in the clipboard until you override it or restart your computer. Additionally, through some applications, it is possible to view and manage your clipboard history.