Thank you for joining us here in the Community, @invalidmemory.

I can provide some information about adding automatic late fees.

Automatic late fees are available in all versions of the QuickBooks US version. You can turn it on under Account and Settings, then Sales​​​​​​. Refer to the steps provided by one of my colleagues above ZackE to customize late fees.

Refer to this article for the detailed steps: Set up and apply automatic late fees to invoices.

If you refer to the Canada version, we don't have control over the availability of features to be added. 

I recommend you check on this link: QuickBooks Feedback Page. This way, you'll be able to vote for this feature to be added. Our Products and Development team are working to improve our service and serve you better. 

I'm also adding this link for the feedback page to check for other feedbacks sent. You can vote for the features you want to add: Customer Feedback for QuickBooks Online.

You can always ask me for additional questions about adding automatic late fees. I'm always here to help.