File I/O, or file input/output, refers to the process of reading from and writing to files on a computer. This allows programs to store data permanently, retrieve it later, and manipulate it as needed. File I/O is essential for applications that require data persistence, such as databases and text editors. In programming, file I/O operations typically involve opening a file, performing read or write actions, and then closing the file. Common file formats include text files, CSV files, and binary files. Different programming languages provide libraries and functions to facilitate these operations, making it easier for developers to manage data.