Order Form Save and Submit

Order Form Save and Submit

Hi
i am creating an Order Form for Customers.
I want to implement a functionality so that customers can

        SAVE
        SUBMIT

an order. SAVE means data is saved for later review SUBMIT (approve) means we want to purchase this (the Customer user who submits can also be a different user than the user who creates /SAVEs the order)
Also is there a functionality if this is SUBMITed to get this somehow digitally signed by the customer
How would you approach/solve this?

Thank you!
Kind regards
Lambert