Some type of file extensions

.doc	Word 97–2003 Document
.docm	Word Macro-Enabled Document
.docx	Word Document 2007 & above
.dot	Word 97–2003 Template
.htm, .html	Web Page
.mht; .mhtml	Single File Web Page
.odt	OpenDocument Text
.pdf	Portable Document Format
.rtf	Rich Text Format
.txt	Plain Text Format
.xml	Word  XML Document
.csv	CSV (Comma Separated Value)
.dbf	Dbase III and Dbase IV
.htm, .html	Web Page Hypertest Markup Language.
.mht, .mhtml	Single File Web Page
.ods	OpenDocument Spreadsheet
.txt	Text (Tab delimited)
.xls	Excel 97–Excel 2003 Workbook
.xlsx	Excel Workbook Office 2007 & above
.xlt	Excel 97 - Excel 2003 Template
.xltx	Excel Template Office 2007 & above
.bmp	Device Independent Bitmap
.gif	GIF Graphics Interchange Format
.jpg or .jpeg	Joint Photographic Experts Group
.pdf	Portable Document Format
.png	PNG Portable Network Graphics Format
.pot	PowerPoint 97–2003 Template
.potx	PowerPoint Template
.ppam	PowerPoint Add-In
.pps	PowerPoint 97–2003 show
.ppt	PowerPoint 97–2003 Presentation
.pptx	PowerPoint Picture Presentation
.rtf	Rich Text Format
.tif	Tag Image File Format
.wmv	Windows Media Video
.xps	XML Paper Specification