We start from the order. A Shopify sale becomes a sales document in the company file you picked when you connected, in the order’s currency, with the customer matched by name or email, and we set the quantity on hand on the matching QuickBooks item. Change a price in Shopify and we write it onto the item too, so margin reports in QuickBooks stop drifting from what the shop charges. The SKU is how items pair: Shopify holds 255 characters, QuickBooks 100, so anything longer is cut to fit, and the two stop matching without an error. Give both the same SKU under 100 characters.
A payout app starts from the money that reached your bank. Shopify pays out every few days; the app takes that deposit, splits it into sales, fees, refunds and tax, and posts one entry that matches the bank line to the penny. That’s what an accountant wants at month end, and QuickBooks Connector for Shopify (Intuit’s own, free, set up from inside QuickBooks Online) does a plain version of it. Intuit’s listing has the current details. If that’s your whole job, use it and stop reading.
Cancellation handling depends on the document and verified payment state. Paid, partially paid or refunded documents are retained for reconciliation; cancellation alone doesn’t authorize a refund. Nothing ever comes back out of QuickBooks: it’s your books, not a shop, so there’s no listing to create, no order to import from it, and no tracking number to send it. The quantity we set there is a figure for your reporting and your accountant, not a count a customer can buy from.