Hi there, @Chris.
In generally accepted accounting principles, whenever you create an invoice, it's automatically assigned to accounts receivable (A/R) and sales accounts. An invoice acts as a request for payment, and with that said, it is treated as a receivable.
If you've already received the payment for the product you've sold, you'll need to create a sales receipt as proof of payment for the transaction you've processed. These are the steps:
- Access your QuickBooks Online company.
- On the left navigational bar, click the +New button.
- Select Sales receipt.
- Choose the customer from the Customer dropdown.
- Input the sales information, such as the payment method.
- Enter line items for the product and services you sold.
- When done, select Save and send to email the receipt.
For further details, see this page: Create and send sales receipts in QuickBooks Online.
In case you haven't received the payment, feel free to visit this article to learn more about the process: Record invoice payments in QuickBooks Online.
@Chris, I'll be here in the Community space if you need assistance performing specific tasks inside QuickBooks. Have a good one!
