We would like to add our proof of payment (bank file as pdf) to our Bill payment as attachment and send it including our remittance advice to our suppliers.

Hi there, accounting-board.

I'm here to share information about adding attachments to bill payments in QuickBooks Online (QBO).

Currently, the Attachments section in QBO is intended for record-keeping only. The attached files will show on your end, but they won't carry over when you send them to your supplier.

Instead of using the Attachments function, you'll want to download the Remittance Advice. Then, send it together with the receipt or deposit slip using your own email provider.

To download the Remittance Advice, here's how:

1. Open the Bill Payment transaction.
2. Click the Print button.
3. Select the download icon at the top right part of the Print preview screen. 

Our developers might change how the information is reflected when emailing remittance advices. They might include the feature to have the attached files on the email messages.

For more information about managing attachments in QBO, consider checking out this article: Add or delete attachments in QuickBooks Online.

I also recommend visiting our website for more tips and other resources you can use in the future: Self-help articles.

Please let me know if you have additional questions about this or anything else QuickBooks. I'm always here to help. Stay safe.