Note, if you put an ASK field (not the REF to it) in a header or footer, it will be triggered every time you print (actually every time you view the print preview).

If it is in the body of the document, you can use Ctrl-A, F9. This updates all fields in a document and will trigger the ASK field.

Unless you want your customers editing your documents, you should not be sending them in Word format but rather in PDF.