Invoice after adding manually calculated shipping charge

I have wholesale orders that I enter manually for my customers. I have a 3rd party fulfillment center that uses their shipping account to ship on my behalf.

How do I create an order, submit it to the fulfillment center, then add shipping once I know the cost and bill the customer?

I’ve been marking it as paid so that it gets submitted to the fulfillment center. Then I have to import it to quickbooks online so that I can add shipping charges and bill the customer. I’d like to do it all in Shopify if possible.

I saw this message - but I still have questions.
https://community.shopify.com/c/payments-shipping-and/take-customer-order-without-processing-payment-till-after-a/m-p/401193/highlight/true#M17743

What solution did you come up with for this? Split payments was mentioned to me by someone, but that won’t handle this specifically. We need to get freight rates before quoting accurately.