File types are like embedded signatures, telling the operating system that this type of file can be opened by this  software or program and also to  associate with it properly.  A  file extension is one or several letters at the end of a filename. Usually three or four letters,  Filename extensions usually follow a period (dot) and indicate the type of information stored in the file.  One good example is “Warcraft III.exe” the .exe file extension this means that Warcraft III is an executable program file.  “.exe” file extensions are sometimes dangerous to open especially when you don’t know the file.  If you have files such as “.exe”, better not open it because some of this types are viruses and this can surely ruin your entire operating system especially for Microsoft Windows.

To show hide your file extension for windows is just go and open My Computer then click Tools menu and click Folder Options and click the View tab.  You should have the same as the image below:

If you want to show file extensions then you can always check the box and click apply.  Conversely, you can uncheck it if you dont want to see the file extension.

One disadvantage of this for most users is that when you rename the file and the extension is remoced the file will no longer work.  One example is that when you have a “example.doc” which is a MS Word File  and rename it to “myproject” the file will not work unless you write the file extension.  Renaming it back to “myproject.doc” will rename the file and will work on .doc editing software.