I'll share some information about making ACH payments with QuickBooks Online, carlos4.
Melio is a third-party online payment service provider offering free-of-charge bill payments and bank transfers to customers. As @Fiat Lux-ASIA mentioned, you can use this app to integrate with QuickBooks Online (QBO). Check out this link so you can get the app: Connect Melio with QuickBooks Online - Intuit
Once done, all companies who have Bill Pay will see the new " Schedule payment" option. But, only Admin users can see the Bill Pay feature. All non-Admin users are blocked and will be prompted to contact their company's Admin user for assistance.
After that, you'll have 3 options when making a payment. You can choose Bank Transfer/ACH, Credit Card, or Paper Check. To give you more overview of Melio, check out this article for more information: Bill Pay By Melio For QuickBooks Online.
Furthermore, QuickBooks provides certain kind of reports that tells you about different aspects of your business. Learn how to customize them so you'll get the information you need. I've added this article for your guide: Customize Reports In QuickBooks Online.
If there's anything else that you need to know about integration or making ACH payments, drop a comment below so I can get back to you.
