A file extension is a set of characters at the end of a filename that denotes the type of file. File extensions are used to help identify the contents of a file and to determine what type of software should be used to open the file.

Most computer systems use file extensions to determine the file type. The file extension is usually three or four characters long and is preceded by a period. The file extension is followed by the filename.

Some common file extensions include .jpg for images, .pdf for PDF files, and .doc for Word documents.

The file …