Win7 text document can not directly modify the suffix is why? What to do?

1. Reasons that cannot be modified

Because the suffix name of the file in the default settings under Win7 is hidden, it must be removed before it can be displayed again.

2. How do I change my settings?

(1) First, we open the Control Panel from the Start menu, which is where you change your computer settings.

(2) then select "Folder Options" under the Tools menu in the options in the Control Panel to further set how the computer files are viewed.

(3) When the folder option is open, the menu jumps to "view".

(4) Then drag the progress bar to the bottom and find the " Hide extensions for known file types " option, uncheck.

(5) This displays all suffix names, right-click, select Rename, and modify the suffix to what you want.

Win7 text document can not directly modify the suffix is why? What to do?