Action

Apply to Shipping Amount

Total = (Subtotal - Discount Amount) + Shipping 
Total = (Subtotal + Shipping) - Discount Amount


Apply the rule only to cart items matching the following conditions (leave blank for all items).

Free Shipping

Noprevent giving free shipping
For matching items only
give free shipment to the items that match the conditions you list in the block titled "Apply the rule only to cart items matching the following conditions"
Example: If you say category is XX or YY then these get free shipping. Products from other categories are still included in the shipment cost calculation.
For shipment with matching items
give free shipment to orders that contain matching items listed in the block titled “Apply the rule only to cart items matching the following conditions”
Example: if I have a product from category XX, my whole order will obtain free shipping even if I have products from another category. If there is no product entitled for free shipping in cart, the free shipping will not be applied in the order.