What are the different license types?

Here are the different license types in Vtiger CRM:

Standard: Gives users access to all the modules. You can control access through profiles.
Single App User: Gives users complete access to one of the five apps – Marketing, Sales, Help Desk, Projects, Inventory, and read-only access to records in other apps.
Light Agent: Gives users complete access to Organizations, Contacts, Comments, and Calendar, and view and create access to Cases and Internal tickets.