The Storefront can charge a handling fee based on your predefined rules. For example, your business may charge a handling fee for international customers, for shipping oversize packages or perhaps for receiving an EFT (wire transfer) payment.
You must first enable the Handling feature under Configuration > General. Once enabled, you can configure the handling method and rate from the Configuration > Handling menu. Click Add New and give it a name (e.g. "Packaging ") to create a new handling method and select a handling rule. You can assign a tax class if this handling method is taxable.
The rate formula can also use XSL transform to calculate the handling charges. The expected output should return the calculated handling amount to charge. The Storefront comes with several pre-defined rules that you can simply modify the values without needing to know XSL. To learn more about XSL, please see the XSL Transform section.
On the Catalog > Products menu, you will also want to tick the Require handling checkbox on your product variants. This ensures that only those products will participate in the handling calculation. If your handling method is using the "Product rate" rule, it will use the amount entered in the product variant's Handling price field to calculate handling charges.