In a QuickBooks conversion, structural data converts — chart of accounts, customers and vendors, open accounts receivable and payable, transaction history, and balances — while software-specific items are rebuilt in the new file. The parts that determine whether your reports are correct come across; the parts that are conveniences you set up once are recreated on the other side.
That split matters because conversion is never "everything or nothing." The figures behind your prior-period profit and loss and balance sheet convert with the history, so those reports still add up after the move. What does not carry cleanly is the layer that lives only inside the old program's settings: memorized reports, recurring templates, custom form layouts, reconciliation report history, and some payroll detail. Those are rebuilt in QuickBooks rather than moved — the numbers they display convert, but the saved views that display them are set up again. We list exactly which of your items fall in that bucket before we start, so nothing you rely on quietly disappears at cutover.