Why is there not a stopwatch on JotForm? I need a way for a restaurant supervisor time how long it took to receive their food order.

You can only add a timer to your form, but it's not possible to allow the users to start and stop it. Please find the widgets here: https://widgets.jotform.com/search/timer 

https://www.jotform.com/help/252-How-to-Add-a-Widget-to-Your-Form.