This just means that you should create a personal copy of the K1 visa packet for your S.O. and your own records. Whatever you send in your initial submission, your S.O. should have a copy of the exact same thing so they are familiar with the packet and can answer any pertinent questions at the time of the interview.
This is true for anything you submit to USCIS. Everyone on VJ normally suggests that you make a copy of each packet you submit so you have it for your records not only to be familiar with it throughout the process, but it case something needs to be re-submitted.
