Tag system for tickets

How can I tag the different support enquiries? Do I really have to create my own property fields to do this, or does a function exist that I have somehow missed? This is kinda basic so I'm hoping for the latter. If not I would encourage HubSpot to develop one. 


Also, in order to have a best possible tag system, subcategories are essential (https://community.hubspot.com/t5/HubSpot-Ideas/Dependent-fields-in-Service-Support-forms/idi-p/20782...)


We need to build reports on the different kind of enquiries, so I'm hoping for a solution in the near future.