The Page Up and Page Down keys are two computer keys that you press to either scroll up or scroll down on documents. The page up and page down scrolling distance sometimes varies depending on which documents you are reading. If the page up of page down key is pressed together with the shift key it will highlight all the text. The page up and page down keys are sometimes called PgUp or PgDn and they are located on the right of the keyboard with page up on top and page down on the bottom.