Power BI dashboards can be shared securely within an organization using app workspaces, where access is controlled by permissions assigned to different user roles. Row-level security (RLS) can be implemented to ensure users only see data relevant to their roles. For sharing outside the organization, Power BI offers the option to publish to the web or share dashboards via secure links, but this should be done cautiously to avoid exposing sensitive data. Alternatively, dashboards can be embedded in secure websites or portals using Power BI Embedded. Regular audits and compliance with data governance policies ensure secure sharing practices.