To allow out-of-stock items to be purchased in the web views, enable the Allow purchase of out-of-stock items checkbox (System Setup > Set up commerce web components > Store configuration).
The backordered purchase is processed as a pro forma order and created as if the item is in stock and will be shipped. However, the product inventory is not affected at the time of the order.
When an out-of-stock item is in the cart during checkout, the cart issues a message about the backordered state. The backorder quantity displayed is based on the product availability at the time the order is placed.
You can customize the out-of-stock and backorder messages that appear during the order process. The out-of-stock message appears on the Product Detail page. The backorder message appears on the My Cart, Review, and Order Summary pages, and in the Order Confirmation sent by email.
If the Allow purchase of out-of-stock items checkbox is cleared, orders containing out-of-stock items can not be processed in the web views.
To enable backorders in the web views
1. From System Setup, select Set up commerce web components > Store configuration.
2. Select the Allow purchase of out-of-stock items checkbox.
3. (Optional) Customize the out-of-stock and backorder messages.
Only one backorder message displays in the web views. The backorder message displayed is based on the backorder option selected on the Backorder Processing window (from Orders, select Set up module, and click Backorders).
4. Click Save.