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Go to Stores > Manage Queue to do that.
There are 7 options that admins need to consider, include:
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Sync Orders: If admins want to sync the old orders, admins will need to sync these fields above before.
Sync Invoice: If admins want to sync the old invoices, admins will need to sync orders before.
Sync existing customers from Magento 2 to Quickbooks
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