Step 1: Ensure that your Brex transactions have receipts and memos associated with them prior to exporting; you can see which ones are missing by using the top filter bar on the Company Transactions tab
Step 2: When you are ready to export, go to the Integrations tab, click on Manage next to QuickBooks, click on Mapping, click on Review & Export, and click on Export
As long as you have not closed your books on QBO, QBO will automatically match any transactions in the banking feed to data ported over by Brex (receipts, memos, and categorization). You will then have the option to confirm if these matches are accurate by clicking on “match” on the right-hand side of each transaction on the banking feed. You should not see any duplicates.