Stripe ACH Payments
You want to start accepting ACH payments via Stripe...awesome.
Setup Plaid and Stripe
Plaid has some great documentation on how to get started, so I'll review this documentation and come back here when you get to "Step 3: Integrate with Plaid Link".
Setup Sprout Invoices
Now you just need to add your Plaid credentials to the payment settings. Everything else is handled by Sprout Invoices.
Test credentials for Plaid can be found here.
Error: Stripe may not be integrated with your Plaid account.
The likely cause for this error is that you haven't yet completed the Stripe Settings, including adding the Live keys.