Power BI dashboards seamlessly integrate data from multiple sources by connecting to various databases, cloud services, and APIs. It supports integration with popular platforms like Excel, SQL Server, Azure, Google Analytics, Salesforce, and many more. Through Power Query, users can extract, transform, and load data from different systems into a unified dashboard. This integration ensures that data from various departments or external sources is available in one place, providing a holistic view of business performance. The ability to merge different data streams enhances data consistency and allows businesses to generate comprehensive insights.