In this article, we have some answers to common questions about the integration.
Toggl entries must be complete (no in-process timers are active). Also, only billable time entries are transmitted. If an entry is not marked as billable, it will not be sent to QuickBooks. Finally, a time entry must be associated with a client in Toggl - otherwise it is ignored.
It matches up Toggl clients to QuickBooks customers by matching the Toggl client name with the QuickBooks customer name or the company name. Toggl time entries that have no association with a client cannot be transferred via the integration because there is no way to associate them with a valid QuickBooks customer.
The integration can handle either scenario. You can configure it to treat all users as QuickBooks vendors, treat them all as employees, or try looking up both vendors and employees to find a match to the Toggl user. The Toggl user name is used to match vendor or employee name, so you'll need to make sure these match up so your time entries sync properly.
Currently no - you can choose only one workspace to sync time entries.