Power BI is a business analytics suite that allows users to connect to data sources, transform data, create visualizations and reports, and share insights. It consists of several components like Power Query for data transformation, Power Pivot for data modeling, and Power View for visualization. Power BI can be used to analyze sales, marketing, financial, supply chain, and other operational data to gain insights. It offers self-service BI capabilities and allows sharing reports through the Power BI service.