What are Files?

an old box of files, old files on a shelf, a computer with file folders coming out of the screen, a stack of floppy disks, and a flash drive

You are probably very familiar with old fashioned file folders and the files they contain. Computer files and folders perform the same tasks only electronically instead of physically.


A file is an object on a computer that contains data or information. It can be thought of much in the same way as a traditional file that could be found in an office’s file cabinet. Like a traditional file, the information of a computer file could consist of anything: a text document, an image, a graphic, or a page of code. On a computer, you can create new files, modify files, read files, open files, write data to the file, and close or delete a file.

Computer files are identified by unique names; no two files will ever have the same name. Although the computer will give a file a name automatically, it is important to change the name to something that easily identifies the file.

File Extensions

Because files can be many different types of things and related to different computer programs, they have an extension in their name following a period. This extension identifies the type of file and tells the computer what program to open the file in. For example, myphoto.jpg is an image file in the JPEG format, myletter.doc is a Microsoft Word document, myvideo.mp4 is a video in the MP4 format. (File types are covered in more detail in the next lesson.)


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