Hi there barrycoleman-net,
it's important that all your transactions are entered correctly for your books to be well balanced. QuickBooks Online is a great tool able to help you create and send invoices to your customers so they know the amount owed to you for your services. I can provide some information about late fees.
In the Canadian version of QuickBooks Online, there isn't the option to automatically apply late fees to invoices, so it would need to be added manually as a line item. I can see that this would be a feature you would like to see in QuickBooks Online to help with your sales management. I recommend you put your feedback into the system by going into the Gear icon, then Feedback. These comments are considered by our developers when creating new features for the software.
If you have any further questions, feel free to ask them here.
