Hello,
A standard SAP installation would create two users: "SAPService<SID>" and "<SID>adm", where "<SID>" is the three letter system ID chosen for this system.
When you logon with <SIDD>adm your command prompt window will have all the environment settings required for the saplicense program to work.
You might also want to use saplikey instead of saplicense (SAP note 1227762).