adding to the great answers of Jack and Mikael you might be also interested in the ITSM guide, published by Atlassian.
While I see the linked documentation gives a precise answer on Jira configuration the ITSM guide can give more explanatory information about the whole concept and glossary:
In case of detailed questions, of course, Community is always a great place to come back to and ask more.
Hello Community! Quick disclaimer: We are running a contest on Community (The Atlympics!) from July 23rd - August 8th of 2021. If you are interested in participating in this contest (prizes! ...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events