Bank and credit card account connections don’t carry over from QuickBooks Desktop, so you’ll need to connect these accounts in QuickBooks Online.
Go to Banking from the left-hand navigation and select Connect account. Then follow the on-screen instructions.
Note: When you’re connecting a bank or credit card, many financial institutions allow you to select the starting date for the transaction download. Choose the day after the last statement date from the final reconciliation carried out in QuickBooks Desktop. This helps prevent duplicate transactions from being recorded in QuickBooks Online.