Hi saasexec,

Currently, QuickBooks Online supports Single Sign-On. You need to set up the authorization flow so your users can connect their QuickBooks Online companies to your app. There are a few ways to handle the UI:

• You can add a “Connect” button to your app’s UI so users can start the authorization flow directly.
• You can implement Intuit Single Sign-on to simplify the sign in experience.

You can check this link for more information about this option: Implement Intuit Single Sign-on.

I'll be around whenever you have other concerns with managing your QuickBooks account. Keep safe!