QuickBooks integrates with several invoicing websites to help manage your transaction manually or automatically. That being said, I recommend seeking help through another forum, called Intuit Developers, where you can find and connect with our developers who can suggest what app to use and help with integrations. Here's the link to the website: Intuit Developers Community.
I'm adding these links below just in case you're interested:
If you have any questions with QuickBooks invoicing can link to website and other topics, feel free to connect with me any time. I'll be right here to help. Have a nice day.