How do you generate automatic receipts when payment is received for an invoice that was sent to a customer?

I appreciate you sharing your query when sending receipts automatically for paid invoices, WHAH. 

It's a good idea for QuickBooks to offer a function that enables the option to send receipts automatically. However, as of this time, this option is unavailable. If you've created and sent sales invoices to your customers, you can manually save and email the payment received to record the invoice sent or save and close to marked the invoices as paid using the receive payment feature.

If you haven't sent an invoice transaction yet, you may create a sales receipt entry any time your customer immediately pays for the products or services at the time of sale. To do this:

1. Go to the + New icon and select Sales Receipt.
2. Choose the customer from the Customer dropdown.
3. Enter the sales info, such as the Payment method.
4. From the Select a product/service ▼ dropdown, tap the product or service that you sold.
5. Once done, click Save and send to email the receipt.

In addition to that, if you use a separate point-of-sale system or if you simply don't invoice customers, you can enter a single sales receipt to report the total daily sales in QuickBooks. This saves you time while keeping your income reports accurate.

Moreover, you may consider running specific reports to help you review business finances and other accounting data.

I'll be on this thread if there's anything else you need further assistance with when managing payments from customers. Let me know any time below, so I can back you up. Keep safe and have a good one!