Here is the problem I have. So most part I sell are out of stock now but I let my customers pre-order. Since the parts won't be here two weeks from now I charge the payment right away. But my problem is when I do that some products shows as FULFILLED and some says payment PAID but UNFULFILLED. Why is that? I would like them all to say UNFULFILLED until I ship the item.
Their status depends on the status of the line items in the order.
If you the order status is "fulfilled", it means all line items in the order have been marked fulfilled.
"Partially fulfilled" means 1 or more line items, but not all have been marked fulfilled.
If you didn't manually mark them fulfilled, then check your fulfillment settings in Settings > Checkout > Order processing, you may have automatic fulfillment enabled.
If I had automatic order fulfillment then it will fulfill all of them. Anyway I found the problem. I downloaded an app so I could send my customers a link to installation instructions for my product. So what was happening is the app sent instructions as soon as the item was purchased and shopify program marked it as fulfilled.