You probably need the following:
Maybe you need a few other job classifications. Perhaps there should be an order handler that takes the pizza from the cook and prepares it for delivery. Or maybe that should be the order-taker's job?
In thinking these thoughts you are doing something close to object oriented design. It is not that easy to get right, even for familiar situations. If you were designing your pizza delivery business you would probably spend several weeks (or months) designing your business plan. When you have the final design, you hire employees and buy pizza-making material.
Then it is run time.
Once your pizza delivery business is up and running, will your employees need to communicate with each other?