The Power Query journey, as a powerful ETL (Extract, Transform, Load) tool, begins with its primary function of extracting data from various sources. It allows users to load data from a wide range of sources, ranging from simple file formats like CSV, TXT, Excel, and PDF, to more complex sources such as entire folders of files or databases like SQL Server. Additionally, Power Query supports data extraction from online sources, including websites, APIs, and cloud-based services, making it a versatile solution for handling both structured and unstructured data.