Hi Devendra,
It is depend on your package and/or based on SAP software functions user performs, please refer below definitions for some user types.
Professional: users who perform more wider and important operation/administration (Monetary or HR related critical function) related functions
Limited professional: user who perform limited function in SAP
Employee: who perform very specific activity or non critical activity
Example based on function criticality
Create: Professional
Change: Ltd Professional
Display user: Employee
Similarly it is depend on number of functions performed by users, the more wider the SAP software functions used the higher the license type.
Hope this helps.
BR,
Mangesh