I/O Stream and File Manipulation refer to handling input and output operations in a program, enabling interaction with the user and data storage. I/O streams abstract data flow between devices or files, allowing reading from or writing to various sources like the console, files, or network streams. File manipulation involves operations such as opening, reading, writing, appending, and closing files, often using libraries or frameworks. Languages like C++ provide classes like ifstream, ofstream, and fstream for file handling, while others use similar constructs. These tools are essential for managing persistent data, logging, and processing structured or unstructured information efficiently in software applications.