can JIRA CORE be set up like a ticketing system/IT help desk? Or, do we need Service Desk?

[NIck Medrano]

I am new to Jira Core. Is it possible to set up a basic custom workflow for a 'ticketing system' like an IT help desk? Or, do we HAVE to purchase Service Desk? 

[Nic Brough -Adaptavist-]

Yes, you can, Jira is an issue tracker at it's heart.

Without Service Desk though, you will have no portals or SLAs, and your issues will be fully exposed to the end-users.  You'll need to work hard to build queue-like functionality and reporting (although there are some Apps in the marketplace that can help)