A file, in the computer world, is a self contained piece of information available to the operating system
and any number of individual programs. Information inside the file could consist of essentially anything but whatever the file contains is likely related somehow.
A computer file can be thought of much like a traditional file that one would find in an office's file cabinet.
Whatever program uses an individual file is responsible for understanding its contents. Similar types of files are said to be of a common "format." In most cases, the easiest way to determine a file's format is to look at the file's extension.
Each individual file in Windows will also have a file attribute which sets a condition to the specific file.
Files in any operating system are stored on hard drives, optical drives, and other storage devices. The specific way a file is stored and organized is referred to as a file system.
Examples: "For years I had a text file that I stored important telephones and addresses in. A few years ago, when I first started using Microsoft Excel, I moved the information that text file to a new Excel file I created. In this new file format, I can sort names and display the information in new ways."