File extensions are used to identify the file of a computer. There are so many file extensions over the computer world, but there are some most known file extensions are
.DOC OR .DOCX = Microsoft Word
.XLS OR .XLSX = Microsoft Excel
.PPT OR .PPTX = Microsoft PowerPoint
.PDF = Portable File Format
.PSD = Photoshop Document
.JPEG OR .JPG = Joint Photographics Expert Group
.PNG = Portable Network Graphics
.GIF = Graphical Interchangeable File Format
.AVI = Audio Video Interleave