I appreciate you for sharing this concern in the Community, @Workafrolic1. Let me provide you with the right way to add a negative number to your sales receipt.

Let's start with editing your sales receipt, you can follow these steps:

1. Go to the + New.
2. Select Sales receipt.
3. From the Customer dropdown, select the name of the customer.
4. In the Deposit To dropdown, select the Undeposited funds.
5. Once done, click Save and close.

Once the transaction is assigned to undeposited funds, you can proceed with the bank deposit and manually add a negative line item. Please refer to the steps provided by my colleague above.

Additionally, customising your sales form contents is a breeze in QBO. For a detailed guide, please refer to this article: Customise invoices, estimates, and sales receipts in QuickBooks Online.

If you have any further questions or need additional assistance with managing sales receipts in QuickBooks Online, please do not hesitate to click the Reply button. We are here to support you and will respond as promptly as possible.