QuickBooks Integration is the Store Manager addon, that is it's a part of Store Manager (it is already built-in) and should be registered with a separate license key. So in order to use the addon you have to install and register Store Manager and se tup all required settings first.
To start using the QuickBooks Integration addon you have to go through the following steps:
6. Check your products on QuickBooks.
Check our License Agreement and the following articles: