The security framework in AX is used to ensure that the user experience is tailored to each user's needs by filtering out functionality that is irrelevant to the users.
To do this, AX uses three main areas of the security framework:
License codes give access to different modules in AX. In the customer's environment, the customer will have a customized set of license codes activated in AX, depending on which modules they have bought.
Value added resellers and independent software vendors get their own set of license codes that normally include most of the standard modules within AX.
You can look at the existing license codes in AOT by going to Data Dictionary | ...