In VetView, security is controlled through a long list of individual privileges that are attached to individual screens. A particular screen's privileges are completely independent of another screen's, even if the functionality is similar. Giving a user the "Add Charges" privilege on the Accounting Screen does not mean they can add charges on the Client Screen. This allows for maximum flexibility.
Privileges can be grouped into custom roles. Those roles can then be assigned to users. A user may be in multiple roles.
Security privileges can be assigned to Security Roles or individual users (via the Role Management or User Management screens).
For a more technical look at VetView security, read the page in our technical docs about security.