How can user requests be categorized, are there any examples?

Question

Helpdesk

Hello colleagues.
We are a budget institution. We are engaged in the support of several OIV in the region.
We use OTRS for work.
Now the task is to set the right services in order to more accurately categorize user requests for subsequent reporting and fixing those responsible for this or that work. Before reinventing the wheel, I googled, but did not find the answer.
I would like to know how it is implemented by other IT specialists.
An example of how this is approximately implemented here:
Service: Office equipment.
Subservices: Cartridge Replacement, Refueling, Repair, Relocation, Installation

Answer 1

Well, based on experience, I would, on the contrary, reduce the number of subcategories. Alternatively, the following request categories can be specified:
In addition to request types, categories are assigned, for example:
------------
Here, something like this.

Answer 2

Decide what you want from categorization.
As a rule, categorization is introduced to normalize the process of fulfilling applications. If this is your goal - then select all the typical tasks that you perform as part of support - these tasks will be your subservices. Group them by services (it is possible on the basis of a group of performers - it will be more convenient in the end) and add the "Other" subservice to each group. Everything, on the basis of such categorization, it is possible to solve the problem of rationing.