Create Dynamic Invoice

I would like a plain first page that prompts the user with a single box labelled "please enter either order or despatch number" when submitted it should do the following: If number begins "dp-" or "Dp-" or "dp-" then use Despatch invoice else use order invoice. For despach invoice (copy attached) the top and bottom are static but the details section is dynamic depending on the number of items in the despatch. For Order Invoice (copy attached) the top and bottom are static but the details section is dynamic depending on the number of items in the order. In the user should be given the option to either download the file as a PDF or print the page from within the browser. I have attached the background images for your reference. I have a attached a sample invoice to show you the output (this is an order invoice)