I can share some information that can help you with exporting your bank transactions to QuickBooks Online (QBO), @Warren K.

You can use a 3-column or 4-column format for your CSV file. The 3-column format has a Date, Description, and Amount column while the 4-column format has a Date, Description, Credit, and Debit column. Refer to the screenshot below:

You can also search online for file converters that can easily convert your file to a CSV format.

Also, please take note of the following pointers:

1. Please ensure that any zeroes (0) in the CSV file are removed and the corresponding cells are left blank instead.
2. In the Description column, kindly ensure that any numerical values are removed. Thank you. Remove the word amount from the Credit and Debit column headers.
3. To ensure consistency, it is recommended that all dates follow the format of DD/MM/YYYY. Please make sure to use this format for all date entries.
4. Mac users must save the file as a Windows CSV file.

For more information on how to edit your CSV file, check out this article: How to format CSV files in Excel to import bank transactions into QuickBooks.

Once done, you can now import the file to your account: Manually upload transactions into QuickBooks Online. It'll guide you with categorising the transactions once uploaded to your account. 

In case you're having problems, here's how to resolve common errors for importing bank transactions using CSV. 

Let me know if you need further guidance importing your CSV file. The Community is always here to assist. Have a great rest of the day!