If I recall correctly, those are the function keys on the keyboard. They are not part of the HMI screen. I assume you have a keyboard as part of the HMI?
Each screen can use one of three sources for the function key logic, and this is displayed with a coloured triangle in the bottom left corner of the function key.
Global Screen - every screen will do the same thing when you press a key. I like putting a help dialogue on F1 (valve colour code, pipework colour code ...)
Local template - helps to keep a consistent theme to parameter screens, P&ID screens ect.
Screen - each screen can have specific actions associated to a key, i.e. move to next parameter screen.