You can find an overview of the QuickBooks Integration in Teachworks:
Teachworks connects with QuickBooks Online. The "Simple/Easy Start" and "Self-Employed" subscriptions do not include the required features to support this integration. All other plans will support the Integration.
Teachworks does not connect with the Desktop version of QuickBooks.
Syncing is one-way from Teachworks to QuickBooks.
Teachworks syncs customers, services, invoices, credit notes, and payments.
The following items must be entered manually in QuickBooks.
Voiding invoices and credit memos (if they have been voided after syncing to QuickBooks).
Allocating payments and credit memos to invoices.
Refunds
QuickBooks does not support the "Tax Inclusive" tax treatment on invoices.
You can connect multiple Teachworks Accounts to one Quickbooks Account. You can find more informaion about doing this in this article: Syncing Multiple Teachworks Account to One Quickbooks Account.