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 ...

The default setting for Windows is to not display a file's extension, which is the last period in a file name followed by 2 or 3 letters. Therefore, when viewing files in Windows you would only see ...

Microsoft hides file extensions in Windows by default even though it's a security risk that is commonly abused by phishing emails and malware distributors to trick people into opening malicious files.