1. Figure out which refund you're actually doing. Most categorization mistakes come from grabbing the wrong form, not from picking the wrong category. A straight refund with no invoice attached is different from refunding money that's sitting as a credit against an existing invoice.
2. For a refund with no invoice involved, open a Refund Receipt. Go to + New, then Refund Receipt, pick the customer, choose the payment method, and select the account the money is leaving from.
3. Add the same product or service lines that were on the original sale. That keeps the refund netting against the same income account the sale originally hit, instead of creating a cost that looks unrelated to any revenue.
4. For an invoice overpayment or an existing credit memo, don't use a Refund Receipt. Open Receive Payment for that customer, apply the credit, and check the box to refund the amount to the customer before saving; QuickBooks generates the refund check for you. Doing it manually works too: + New > Check, category set to Accounts Receivable, same customer, same amount, then apply the check and the credit together.
5. If the original payment ran through QuickBooks Payments, choose Credit Card as the refund method. That sends the money back to the customer's card directly instead of issuing a paper check for money that never physically left as cash.
6. Save, then check the register. A customer refund should reduce cash out and net against income, not show up as a bill or a vendor transaction. That's a different flow entirely, for money coming back to the business rather than going out to a customer.