It was in the 1990s that Microsoft chose the doc extension for their proprietary Microsoft Word processing formats. Almost everyone would have used the doc file format, whenever you write a letter, do some work or generally write on your PC you will use the doc file format.
Historically, it was used for documentation in plain-text format, particularly of programs or computer hardware, on a wide range of operating systems. Doc (an abbreviation of document) is a file extension for word processing documents it is associated mainly with Microsoft and their Microsoft Word application.
