Dell P2723DE 27" 1440p USB Type-C Hub Monitor - Manual (Page 49)

Setting up the monitor │ 49
• When the monitor and the PC power state are both ON, press and hold the
monitor power button for 4 seconds , the screen prompt will ask if you would
like to shut down the PC.
• When the monitor and the PC power state are both ON, press and hold the
monitor power button for 10 seconds , the PC will shut down.