That depends on the type of file. The main one is .mdb which stands for Microsoft Database.
.accdb is the extension used for Access 2007 and 2010.
.mdb is the file extension used by Microsoft Office's Access program and it marks a file that is a database.
.accdb is the file extension for Microsoft Access and has been used since Access 2007. The previous file extension was .mdb.
A .ppt file is a file to be used in the Microsoft PowerPoint software.
.docx The extension docx is used in Word 2007.
.dbs
".doc" in versions of Microsoft Word before 2007".docx" in Microsoft Word 2007 and later..docMS word
the Microsoft word files are called document
The olp file type (extension) was used by Microsoft for Office Live Package(?) to allow for the backup and restoring of Office Live websites.
A text file created in Microsoft Word typically receives the extension .docx. This format is used for documents created with Word 2007 and later versions. If you save the document as a plain text file, it would have a .txt extension instead.
xlsx is the main extension used for Excel 2007.
The CUR file extension is only used by Microsoft's Windows operating system for cursor images.