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 ...

A file extension, or file name extension, is the letters immediately shown after the last period in a file name. For example, the file extension.txt has an extension of .txt. This extension allows the ...

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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 ...