Hi @kirihong,
Orders is only incremented when scPurchase is present in the events string (assuming this is Classic Analytics).
All Orders are counted towards this; Adobe doesn't care on the amount of revenue, be it 0, half, full, etc.- it would be whatever is being passed as part of the product string. So for a day date range, Orders will count every order for that day, ie. every time someone visited a page where scPurchase was present in the events string.
There are many, many other things that come into play for the orders, events, & products variables, however I'm not sure if you need that level of detail for your question.
https://experienceleague.adobe.com/en/docs/analytics/implementation/vars/page-vars/products