If you're using a USB cable to connect your controller to your PC, use a flashlight ... pen to find your PS4 controller. Your PS4 controller will be listed as Wireless Controller in this menu.
Use a Bluetooth adapter like the Mayflash Magic-S Pro to connect your controller wirelessly This article explains how to use ...
If you want to use your PS4 controller on your PC outside of Steam, you can either connect it via Bluetooth ... click "Bluetooth." 7. Click "Wireless Controller" in the list of available devices.