Windows Remote Desktop server configuration

You could read the Microsoft Documentation.

For Windows 10, search for remote desktop settings. You can enable remote desktop and give selected users access. Note that any administrative account has access by default. Adding other users will add them to the Remote Desktop Users security group.

For Windows 7 open up the System Properties and choose the Remote tab. Select Allow remote connections to this computer. Leave Allow connections only from... ticked unless you find that your remote client will not work with this setting. You can choose the users to allow (again, administrative users have default access), or edit the Remote Desktop Users security group directly.

If the Windows Firewall is on it should be configured by default to allow RDP connections.

Note that on a desktop, an RDP session will lock the local console so you cannot see what is happening on the screen attached to the system being controlled. You can log in to the system using the credentials of the logged-on user - this will end the RDP session. You can also log on (locally or remotely) with another user with administrative powers and kick the current user off (there is a warning first allowing you to abort the connection attempt). The logged on user will lose any unsaved work in this case.