Enter the statement Ending balance and Ending date. If you aren't prompted to enter an ending balance or statement date, you already have a reconcile in progress for that account. If necessary, you can edit the ending balance or ending date on the Reconcile page.
Enter any additional information requested. If your statement doesn't have an amount for any of the additional fields, you can leave them blank. For accounts connected to online banking, the Service Charge, Interest Earned, and Finance Charge (credit cards) fields do not appear, as these entries are downloaded automatically.
Select Start reconciling to open the Reconcile page.
Once done, you can now start comparing your transactions to ensure the information in QuickBooks matches the information on your bank/credit card statement.
For further details about reconciling an account in QBO, you can check these articles: