Jira uses issue types to define the purpose of issues, while the Jira Service Desk uses request types for the same purpose. In fact, each request type is mapped to an issue type behind the scenes. The one key difference between the two is that a request type is what is shown to the customers, and a more descriptive display name is used. For example, an issue type is called Incident, and the corresponding request type will be called Report system outage. You can think of request types as issue types with a more informative display name.