Returning a single item to inventory
If the order in which you are attempting to return an item to inventory only contains that one item, you may perform the return by canceling the order within Shopify itself.
To return the one and only item within an order to inventory, simply click More actions and choose “Cancel Order”
If there are multiple items in the order that you wish to return to inventory, you will want to do so using Edit Order.
Here’s a video walk through of the steps above:
Find the tutorial on how to return an item within a order with multiple items, and many more tutorials here.