We need to keep the system running, servers need maintenance, the client PCs might. The business applications need support, and you need to resolve those 'How do I ?' questions.
Servers, Client PCs, Network hardware and cabling, Wireless, ADSL, Operating systems (Sever and Client), Office and Application software, Cloud hosting, Internet security and plenty more. It all needs to work together.
Choosing all of the interacting elements is Consultancy, keeping it all running is IT Management.