Product Auto Update
If this feature is enabled, any changes that you make in the products feed on Shopify, then it will be automatically reflected for that particular product on Facebook Marketplace.
(If enabled) If any new product is added to the Shopify store, then that product would be automatically added on Facebook Marketplace.
Your order will be automatically canceled on Facebook if the product is unavailable on your Shopify store. This situation usually occurs when the auto-delete setting is disabled.
With this setting, the product would be automatically deleted from Facebook once it is deleted from Shopify.