Each export routes to whatever you pick here. Most bookkeepers already have an opinion about the chart of accounts — this just points at it.
Charge category
QBO product / service
Income account
Crane Labour
Travel
Fuel
Permits
Consumables
Tax
Default tax rate
Applied per taxable line on export
% HST
The first time you export a job for a new customer, you'll link an existing QBO customer or create one — remembered for every export after that. If an export ever fails (expired connection, an unmapped category), the job shows a clear reason and a manual Retry, right in the approval queue.
Disconnect QuickBooks Online?
New job exports will fail until you reconnect — each one will show "Export failed" with a Retry, right in the Approval Queue. Nothing already exported is affected.