To use the app, just download, and it configure it with your PC’s MAC address, IP info and some other stuff. Although you need to have Wake On LAN enabled on your PC. Once you have everything configured, you can then use this command at your phone Cortana wake (computername).
Remotely power up your PC with Cortana using VoiceWake for Windows Phone 8.1
By:
T3chmuz
In: VoiceWake, Windows Phone 8.1, WP