All of the above answers are "workarounds" to the original post/problem, not a viable solution that could simple be built into the app -- just make a field for shipping below the subtotal of the invoice, much like "service charge," but allow it to be changed each time! Yes, I can create a shipping product/line item, but that's not the point. The point is that Square invoicing is not set up to work well with sales being shipped, only in-person sales.
For example, there's no easy way to turn off all the sales taxes for an invoice when it's a tax-exempt sale (I have to manually turn off 3 different tax settings -- city, state, county -- for each line item), and for a large invoice, that's a lot of extra work.
Also, it would be great if I could invoice the customer and have two different fields for shipping and billing -- no, I don't want to ask them when I send the invoice; I already have that information, and I should be able to put that into their customer field.
So, I agree with the OP that Square is not a good option for online sales. These are simple things we need for invoicing our customers. If you are going to offer invoicing, you need to understand what your customers' needs are.
