Power BI Service is Microsoft’s cloud-based platform for sharing, collaborating on, and interacting with data and reports. Think of it as the online companion to Power BI Desktop. While Power BI Desktop (a free Windows app) is where analysts build  data models and design reports, the Power BI Service ( app.powerbi.com ) is where you share and consume  those reports, dashboards, and apps with others. In practice, you’d do your data cleanup, modelling, and report design in Desk