What permissions does a user receive if they have more than one role?

The permissions for a user is a superset of the permissions from all of the roles to which the user is assigned.

For example, suppose that a user is assigned a Project Manager role that includes permissions to approve expenses and also an AP-related role that includes permissions to enter AP supplier invoices, but not approve expenses. Because the user has both roles, they have permission to approve expenses and enter AP supplier invoices.