I can shed a light on that, xelerarg.
if you've set up QuickBooks Payments, you'll get the option to process an ACH bank transfer for your customer’s sales receipt or invoice. This way, you don't have to manually take paper checks.
Once you select Check as the payment method, the Enter Bank info section will automatically show up. You can choose to save your customer's bank information, so you don’t have to re-enter it in the future. Then, get the authorization letter to accept ACH payments right in your QuickBooks account.
For more information about this topic, you can read this article: Process an ACH bank transfer.
With QuickBooks Payments, you can also let your customers pay right in their online invoices.
Do let me know if you have any other concerns or questions by dropping a comment below. I'll be right here to keep helping.