Downloading Files from a Web Browser File Name and File Extension A file name is identification for a specified file, which includes a name and an extension. A file extension is a dot (.) with two or three letter code that tells you what kind of format was used to create the file. For example, Internet. txt is a file name with extension.txt, and internet.zip is another file with extension .zip. They are different files, internet. txt is a text file because it has an extension .txt, and internet.zip is a binary file since it has an extension . ....