We use the draft order process which allows our customers to place an order from an email which have sent them.
If we place an order via POS or take an order over the phone, we can do this for an item that is out of stock, the stock level is allowed by shopify to go below zero and the item is placed on backorder in our warehouse software. When we get new stock in, we can then book it into stock safe in the knowledge that the ultimate stock level will be correct when receiving the products into the warehouse. The backorders can be shipped leaving a stock figure of what is left over.
When you send a draft order to someone via email, it will not let that person place the order if there is zero stock so we cannot build up backorders using this method without setting products to sell below zero.
Is there a way to make emailed draft orders act like the POS system and take stock into a negative position, without us having to switch the item to sell below zero or add stock and reserve in advance?