Data Loader is a tool used to import and export large volumes of data into and out of various systems, particularly in cloud-based platforms like Salesforce. It simplifies the process of managing data by allowing users to perform bulk operations, making it easier to handle large datasets efficiently. This tool supports various file formats, such as CSV, and provides options for data mapping and transformation. Users can schedule data loads, monitor progress, and handle errors, ensuring that data management tasks are streamlined and effective for businesses and organizations.