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 ...

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 ...

You're probably aware that most files have an extension such as TXT or EXE after the file name, even though these are not always displayed in Windows. File extensions are how Windows knows what to do ...