Please Help: ca online examination form

I made a mistake in online form. I got I made a mistake in online form. I got mail from institute that hightlight that mail from institute that hightlight that area and mark the correction and area and mark the correction and seperately add a cover note.My seperately add a cover note.My question is WHICH COLOUR OF question is WHICH COLOUR OF HIGHLIGHTER TO USE ANDwhat does HIGHLIGHTER TO USE ANDwhat does MARK THE CORRECTION MARK THE CORRECTION means ? means ? Thanks in advance Thanks in advance