Thanks for joining this thread, Rescale.

QuickBooks Online journal entries are required to have a counter number, so we're unable to leave this field entirely blank. This means, the option to disable this feature is unavailable in QBO. However, you'll have the ability to control the sequence and use the counting scheme you'd prefer. You can follow the steps provided by colleague @MichaelDL on how to set up Custom Transaction Number in QBO. 

I've also added screenshots for your visual guide:

You may try visiting our QuickBooks Blog regularly. From there, you'll be updated with the features and enhancements that our developers are currently working on.

Feel free to add a comment below if you need anything else.