Could you please share any information related to service modelling any content/ steps of doing the ITSM service modelling.
Service models are a term I've come across in ITIL, they are supposed to "describe the structure of a service (how the configuration items fit together) and the dynamics of the service (activities, flow of resources and interactions)". Other than that, ITIL doesn't give us a lot of guidance and it's hard to find real world-examples.
Generally speaking, models are a representation of something that exists in the real world. They can take many forms and can be simple or elaborate. I would imagine the contents of a model and the effort that goes into creating it will depend on its purpose. So identifying the insights we want to gain from the model should be the first step, allowing us to figure out what kind of model we need.
A service model should probably include a description of the service and how it creates value for the customers, a specification of the service interface, and a list of (major) assets required to provide the service.
In YaSM we collect such information for each service in a process definition document. I have attached the checklist that describes its typical contents, and it hope it provides some useful hints for you.
As for describing the dynamics of a service, value stream mapping is often regarded as a good solution. I would do the mapping in a very simple form, as in this example. (You can add additional information as needed, such as start and end conditions, information flows, required resources, etc.)