These are the different permissions (rights) that can be set for each person:
View
This allows a customer/technician to see his calls or customer info.
Add
This allows a customer/technician to add a new call or customer info.
Delete
This allows a customer/technician to delete a call or customer info.
Modify
This allows a customer/technician to modify his own call or customer info.
Technician
This allows a technician to see all calls or customer info, not just his own.
A default user that does not use a tracking account, only has Add permissions.
A customer who creates a tracking account for himself will automatically receive View, Add, and Modify permissions.
The admin and technicians generally have all permissions, but sometimes you may want a technician who can see everything, but not modify or delete. Many combinations can be made.