Well technically... While making some TAG (Text Adventure Games) I was going to make a Help command but, the Help command is exist and same thing is the Default Commands. How do I Removed or Edit these?

If the user types something which matches the pattern of multiple commands, it will use the one declared last in the file; this means that a new command you create has priority over the one in the core library.

If you aren't using the web editor, I believe it's possible to view and edit the "hidden" elements; although as I don't use Windows I can't advise you on how to do this.