Upload the policy (which I presume is either a Word Doc or a PDF?) to a Drive folder. Then share this file publically on the web using link sharing. Take the publically shared URL and link this up in the instructions to the form.
A better way for parents might be to take the actual wording from the policy, if it isn’t too long, and paste it into the Form as a text field.
I can’t remember if you use SchoolDocs, if that is the case there is a third option I can think of – let me know.