Hi! I'm not sure the best way to ask this but I want to create a hidden sku or two that I'm selling to someone but it's custom to them (hence why I want it hidden). I want to run it through my site to have proper taxes and shipping and so I can keep track of it. It will be a monthly occurrence - is there an easy way to go about this? I was thinking I can create a hidden sku or two and use my client's credit card (with authorization) for the purchase. Or do I create an invoice (look up the tax rates for where it's shipping) and send to the client? But how do they pay the invoice then? Any insight would be super helpful and appreciated. Thank you!!