Document retrieval systems are tools designed to help users find and access specific documents or information from a large collection. These systems use various techniques, such as indexing and searching algorithms, to quickly locate relevant documents based on user queries. They are commonly used in libraries, databases, and online search engines. These systems can handle different types of documents, including text files, PDFs, and images. By organizing and categorizing information, document retrieval systems improve efficiency and save time for users seeking specific data. Examples include Google, library catalogs, and enterprise content management systems.