Tickets within a service desk can be classified into ticket types depending on the purpose that they are raised for. Different teams in an organization may prefer a specific ticket type that works best for them. These preferences are largely based on industry standard practices or primarily for business convenience. 

Workspace Admins can choose their preferred ticket type while setting up the workspace or later from Field Manager> Type. While IT Workspaces support Incidents and Service Requests, Business Workspaces support Cases (which can also be prefixed as Queries/Issues/Requests).

Know more about ticket types in Freshservice.