Make sure that the paper size set in the printer properties is the same as the paper being printed on. It sounds as though she is printing an A4 document with the printer paper size set to "letter".
Incidentally there is no such thing as a Windows 8 document. Windows is the operating system which runs the word processing program in which the story has been typed. This is most likely to be MS Word or Open Office Word processor. Just thought to mention this as if you need more help then we will need to know which program the document was produced in.