Hi mooresac,
Thanks for posting in the Community! At the moment, we don't have an option to customise the statement template. Let me share with you a workaround on how you can add PO number on your invoice so it'll show on your statement.
- Create or open an invoice.
- Enter PO number on Message on statement text box.
- Select Save.
The added PO number will show on the Description column of your statement. You can follow these steps if you would like to change the placement of your logo on your transactions in QuickBooks Online.
- Go to Gear icon and select Custom form styles.
- Select Edit on the Standard template.
- On Design tab, click on Make logo edits.
- Select Placement of your logo.
- Select Done to save.
For your reference, you can also check this article: Customise invoices, quotes, and sales receipts in QuickBooks Online.
Feel free to drop a comment below if you have any other questions, we're here to help you.