A free app for Android, by Bitklog.

This app is a handy utility for turning your computer on or off with just one click. It can be used with any OS, even Windows 10. The app doesn’t require any third-party software or drivers. It works with all network interfaces and is compatible with both Wi-Fi and Wi-Fi hotspots. The app will work with your home network (Wake on LAN) or over the Internet (Wake on WAN). It can be used with any computer that is connected to the Internet.

What is Wake on LAN?

Wake on LAN is a standard that allows you to turn your computer on or off by sending a special packet to it.