Let me help you print the invoices and statements in QuickBooks Online (QBO), sflynn1972.

The option to directly print customer statements to fit for window envelopes is unavailable in QBO. This can only be done on sales forms (invoice, estimate, and sales receipt). You can check out this article for more information: How to print forms for window envelopes. As a workaround, just manually change the paper size of the statement to Envelope #10 when printing it. Let me guide you how:

1. Go to the Sales menu at the left to get to the Customers page.
2. Place a checkmark on the customer's name, then pick Create statements in the Batch actions drop-down.
3. Click the Print or Preview option at the bottom.
4. Select Print, then tick the More settings to view more options.
5. Choose Envelope #10 in the Paper size drop-down.
6. Once done, press Print again to complete the process.

To learn more about the printing set up using different browsers, please see this link: Print sales forms. For future reference, the following articles outline the steps on how to personalize the look on your forms:

• Create and view customer statements
• Customize invoices, estimates, and sales receipts

Please know that I'm only a few clicks away if you have any other concerns or issues. I'll be more than happy to answer them. Have a wonderful day.