We want to add checkbox field at checkout that offers the customer "expedited order fulfillment", which when checked will add a flat fee surcharge in the order totals. Ideally this checkbox would appear in the "shipping options" section of checkout, and the surcharge would appear as a separate line item in the order totals. Is this possible? Would would be the best way of accomplishing this, or what are my best options to implement something like this?
We are using the custom shipping endpoint, and it is working great. I am not sure if we need to hook this custom field into the shipping endpoint or if it can operate separately. Please advise. Thank you.