Hello there, SCSPL.

To integrate PEPPOL to QuickBooks Online, I'd recommend reaching out to their Customer Care Support. They are the ones who configure the settings.

We also have a separate forum intended for engineers, developers, and other QuickBooks users that can help you with the process. You can post your concern here: Intuit Developer forum and search for the application. 

Please feel free to visit us if you have any additional questions or other concerns. Take care and stay safe.