Hi siouxsu,

Thank you for reaching out to us. 

In QuickBooks Online, you will see two balances on a bank account. If your online banking is connected with QuickBooks Online, Bank balance will be automatically updated once the transactions are downloaded. And In QuickBooks balance on your Chart of Accounts will be updated if you've added or matched a transaction from your bank feeds or recorded manually. Please note that deleting a transaction downloaded from your online banking will affect the In QuickBooks balance. You may want to do a bank reconciliation to ensure that the transactions added in QuickBooks Online matches with your bank statement. 

For more detailed information, you can check on this article: Reconcile an account in QuickBooks Online. 

Feel free to drop a comment below if you have any other questions. Have a nice day!