An ETL Tool is a software application used to extract, transform, and load data from various sources into a centralized database or data warehouse. The process begins with extracting data from different systems, such as databases, spreadsheets, or cloud services. This data is then transformed into a suitable format, ensuring consistency and quality before being loaded into the target system. ETL tools are essential for businesses that need to consolidate data for analysis and reporting. They help streamline data integration processes, making it easier to manage large volumes of information. Popular ETL tools include Informatica, Talend, and Apache Nifi.