Welcome to the Community. I'm here to help you run the report you need in QuickBooks Online.
If you're referring to an account in the Chart of Accounts section, there's a report you can use. It will show all the transactions entered into your bank register.
Here's how:
Click the Gear icon in the upper-right corner.
Select Chart of accounts.
Choose an account.
Press the drop-down arrow under the Action column.
Select Run report.
Filter the date range, then click Run report.
If what you meant is a report for the transactions under a customer, you can follow these steps:
On the left navigation bar, select Reports.
Click the search bar.
Type in Transaction List by Customer and select it.