You can access these settings by going to Settings>Global>Inventory Settings
Under the Inventory tab, you can enable the “Allow Negative Fulfillable Quantity” switch. When this switch is enabled, items with negative quantity in their inventory can be seen as fulfillable.
If “Allow Negative Fulfillable Quantity” is disabled, you cannot publish or activate products with a negative stock quantity..
IMPORTANT NOTE: These settings will be applied for all channels.