There are a few ways to do it. Here's one: Control Panel | Network and Internet | Network Connections | select the WiFi adapter and click Disable this network device. Or right-click it and choose Disable. Here's another way: Device Manager | expand Network adapters | right-click the WiFi adapter and choose Disable device.
  I have a windows 11 desktop pc and a laptop.  I have bought a wifi dongle (you plug into a USB 3 port) and the instructions say that I should first turn off the built-in wifi when using it on a laptop. Does anybody know how I can turn off the the built-in wifi?
How turn off wifi