Thanks for contacting the Community with your question about recording ACH payments that have been made into invoices. I'd be glad to lend a hand.
There are just a few steps to record ACH payments from invoices in QuickBooks Online. Here's how:
1. Click the Sales tab in the left navigation bar.
2. Make sure Invoices is selected at the top of the page.
3. Choose Receive payment beside of the invoice you need.
4. The Receive Payment page will open. You can also choose to add any outstanding transactions here.
5. Click Save and new or select the drop-down to choose Save and close.
You're all set. I've got an article for you that offers additional details about recording customer payments. You can check it out here: https://quickbooks.intuit.com/community/Payments/How-to-record-a-customer-payment/m-p/186418.
Keep up the great work and please let me know if you have any other questions. Take care.