File streams are a way to read from or write to files in a computer system. They allow programs to handle data in a sequential manner, meaning that information can be processed one piece at a time. This is useful for managing large files without needing to load everything into memory at once. In programming, file streams can be implemented using various languages, such as Python, Java, or C++. Each language provides specific functions or classes to create, manipulate, and close file streams, ensuring efficient data handling and resource management during file operations.