Do you want the order form to print to a local printer in your parent's business, or a local printer for the user (the user's personal printer)?
One thing you have to consider when programming an applet in java (which is what this would be) is that the applet is ran locally on the user's computer, not the website's server. So if you wanted to notify your parents in some way when an order is submitted, you would have to somehow send a notification to the web server (possibly via a servlet). Now, just because the applet is ran on the user's machine, doesn't mean you cannot modify files on the web server (provided you have the correct permissions). You would probably update files via an FTP query.
Think of this more as a message system. The user inputs a message, then send it. The message goes through the server and notifies the user receiving the message. And then the message being recieved is displayed to the user. You need to figure out how to notify the recieving user (in this case, your parent's business) that a message (or order) has been sent/submitted. I personally do not know how to do this, but other people on this forum may have some additional advice.