Dell P3424WEB User Manual page 50

When the monitor and PC power state are both ON, while you press and hold 4
seconds on monitor power button, the screen prompt will ask if you would like to
shut down the PC.
USB-C
Press and hold 4s PC will shut down
Slide to shut down your PC
When the monitor and PC power state are both ON, while you press and hold 10
seconds on monitor power button, the PC will shut down.
USB-C
Press and hold 10s PC will shut down
50 | Setting up the monitor