Why sales order not connected to sales invoices to illustrate if the order have done completely wether through one invoices or more than one and also why i cant determine inventory items sold from which location
Welcome to the forum @Ahmed3,
In order to link a Sales Invoice to a Sales Order, you need to either select the Order number from the dropdown menu in Sales Invoice Edit form:
Alternatively, you can simply go to the View screen of your your Sales Order > Copy To > New Sales Invoice
If you want to control the inventory location used to complete the sales order, you need to use Delivery Note. Doing this will trigger other changes in Manager.