IT service management -- often referred to as ITSM -- is simply how IT teams manage the end-to-end delivery of IT services to customers. This includes all the processes and activities to design, create, deliver, and support IT services.
The core concept of ITSM is the belief that IT should be delivered as a service. A typical ITSM scenario could involve asking for new hardware like a laptop. You would submit your request through a portal, filling out a ticket with all relevant information, and kicking off a repeatable workflow. Then, the ticket would land in the IT team’s queue, where incoming requests are sorted and addressed according to importance.