A file extension is a suffix that is added to the end of a file name after a dot. It is usually two to four letters long. File extensions help Windows and other operating systems to know the standard ...

On computers and mobile devices, file extensions are the suffixes that apps append to filenames. When you see an item like "document.docx" for example, the .docx extension tells the computer and the ...

Microsoft introduced the DOCX format, which ends with the extension .docx, in 2007 as an upgrade to its popular word-processing program, Word. DOCX files' incompatibility with earlier versions of Word ...

BearPup sometimes wants to open a file in one program, and other times open it in another. He asked the Answer Line forum for an easy way to do this. Windows uses a file’s extension–the part of the ...