Remote Desktop Protocol (RDP) is a protocol developed by Microsoft. It serves to connect from one PC (client) to another (server) using the local network or Internet connection.
In our days RDP can be used not only on Windows machines but on Android devices as well. Microsoft developed its own app for Android that works as Remote Desktop Client.
With a help of this app you can connect to Windows from Android device via the same RDP Protocol. And actually not only connect but also to fully administer the remote server or PC: install programs, fix issues, remove malware, create and restore backups, reboot, shutdown, etc.