Hi maags1950-gmail-,
To reconcile an account in QuickBooks Online, you'll need to access on a web browser. Also, please note that the Bank balance will only be changed or updated if the account is connected to online banking. The In QuickBooks balance will also depend on the added or matched transactions. You can do a bank reconciliation to ensure that the transactions added in QuickBooks Online matches with your bank statement.
For additional information, you can check this article: Learn the reconcile workflow in QuickBooks.
Let us know if you have any other questions. Have a nice day!