Word will not open or import an InDesign file. Your design, background or graphic will need to be formatted or exported as TIF, EPS, JPG, BMP, or PDF. It can then be inserted as a "picture" into Word. Any editable type will need to be composed Word. Also, your client will need to have the same fonts. For maximum compatibility, I would recommend using only TruType or OTF fonts.
Good luck.
W2