What you're probably talking about is streaming from the Xbox One to the PC. First, you need to be running Windows 10 on your PC, and your Xbox One and Windows machine have to be on the same network. You need to have an Xbox controller connected to your Windows PC. An Xbox One controller connected via USB cable works best and is natively supported by Windows, though an Xbox 360 controller will work too.
Turn on your Xbox One, go into the Settings app and then into Preferences and in the middle column be sure "Allow game streaming to other devices" is checked. Leave the Xbox One on and go to your PC and start the Xbox App that came with Windows 10. The main menu of the Xbox App runs down the left side. Choose the icon that looks (kind of) like an Xbox One, it's the second from the bottom. You should get an "Add a device" pop-up window and your Xbox should be listed (if not you can put in the IP address of the Xbox One and try to discover it that way). Click on your Xbox and it is now 'paired' with the Xbox One app.
After this initial setup you should be able to turn the Xbox One on and off from the Xbox App.
Now from the same screen, click on Test Streaming and let it run; this will give you an idea of how good your experience will be and how high you can set the streaming quality. For best results both the Xbox One and the Windows machine should have a wired Ethernet connection. WiFi should still work but you might have to turn down the settings a bit.
Once the test is complete and you've made note of the best tier of service that gets a green checkmark, click on the Settings icon in the left menu (at the very bottom, looks like a gear) then on Game Streaming where you can set the quality of streaming to the best tier your network can support.
Now click on the Xbox icon again to return to the Xbox screen and click on Stream. From that point on it works as if you were sitting in front of the Xbox One. This is meant primarily for streaming games; some of your media-streaming apps (Netflix is one example) won't work.
To quit streaming, hit Escape on your keyboard. You can turn off your Xbox One from your PC by choosing that option under the More menu (next to Streaming and Test Streaming).