Power BI Data view is a feature within the Power BI Desktop application that allows users to explore and analyze their data in a visual, intuitive way. In the data view, users can create and modify relationships between tables, clean and transform data, and create calculated columns and measures. The data view also allows users to preview their data and ensure that it is properly formatted and ready for visualization. Additionally, users can use the data view to create hierarchies, set data categories, and define the granularity of their data. Overall, the Power BI Data view is an essential tool for preparing and shaping data before creating visualizations and reports.