Before you start a connection, it's a good idea to look up the name of the computer you're connecting to and to make sure Remote Desktop connections are allowed through its firewall.
For permission to connect, you must be on the list of users. To connect to a remote PC, that computer must be turned on, it must have a network connection, Remote Desktop must be enabled, you must have network access to the remote computer (this could be through the Internet), and you must have permission to connect. You can't connect to computers running a Home edition (like Windows 10 Home).
You can use Remote Desktop to connect to Windows 10 Pro and Enterprise, Windows 8.1 and 8 Enterprise and Pro, Windows 7 Professional, Enterprise, and Ultimate, and Windows Server versions newer than Windows Server 2008.