When you are finished using the Information Center Facility, you can exit it by pressing the RETURN PF key (PF 4) or by pressing the END PF key (PF 3) repeatedly until you see a menu panel with an option X to exit.

To exit that menu panel, enter x on its OPTION line and on the OPTION lines of other menu panels that follow. You might then see the READY message or you might be automatically logged off.

If you want to end your TSO/E session, enter logoff, after the READY message.