I'd be delighted to guide you on how inventory works in QuickBooks Desktop (QBDT), Bagya.
To answer your first question, inventories are input once the sales order or invoice is fulfilled.
Secondly, yes, once the item is short or returned, it'll automatically update your inventories. I recommend running your inventory reports to keep track of your inventory status. Simply go to the Reports menu, select Inventory, and run the Inventory Stock Status by Item report.
Thirdly, you can use an inventory adjustment to fix jumps in your Warehouse inventory. You can also use this method for your returned items or adjust the price and quantity of them. Please feel free to utilize this article for the complete details: Adjust your inventory quantity or value in QuickBooks Desktop.
Lastly, to keep your records accurate, you'll want to create a separate sales order for your add-on items. You can also edit your previous sales order and change the date. Nonetheless, I'd highly recommend working with your accountant. They'll be able to guide you on other ways in effectively handling your inventories.
Furthermore, please know that QBDT uses FIFO (First In, First Out) inventory method. This means the first items you received are sold first. You can utilize these articles to learn more about this:
Let me also add this link that can help you track your inventories seamlessly: Set up Advanced Inventory.
You're always welcome to get back to me if you have other follow-up questions about inventories or with your QuickBooks. Fill me in by leaving a response to this thread. Have a good one and keep safe!
