Could someone explain me the difference between them?
Furthermore I have heard that Windows Terminal Server can be used to deploy software to multiple computers in the network in an organisation by creating a GPO. Could someone give me the steps to do this as well?
Remote Desktop Services is set of different roles that work together to provide VDI or remote app experience to the end user. It has following core architecture components:
Window Terminal Services is same as RDS. Microsoft renamed it in 2008. Terminal server essential is session hosts: https://learn.microsoft.com/en-us/windows/win32/termserv/terminal-services-is-now-remote-desktop-services
I am not sure about the GPO part