If you are selling online using other than WooCommerce Platform, then you need to add orders manually.
Go to “Orders” → Add new order →then a page will appear before you fill all the required details in it and “Create Order” → click on Verify and complete.
Here you can see all “Pending orders” on your Online Store. Select Orders through Check Box, then “Hit on Complete”.
Make payment to your Supplier.
Finally, Supplier will process your order and will deliver it to customer’s doorstep.