Classes??

I've got you some insights on how to change the default department in QBO, @Fazfed.

Using classes helps track your transactions by departments, product lines, or any other meaningful segments in your business. So when it’s time to run reports, you have a clear picture of each financial health. 

In QBO, you can change how you tag a class in customer transactions one by one in each row. To do this, here are the steps you can follow:

1. Navigate to Settings ⚙ and choose Account and Settings.
2. Click Advanced and then select the Categories section to edit.
3. Choose Track classes.
4. Select the Assign classes ▼ dropdown, then select One to the entire transaction or One to each row in a transaction.
5. Lastly, click Save, then Done.

For more details, you can check out this article: Track your transactions by class.

In addition to that, I've collected some relevant articles you can use to handle class tracking in QBO: 

• Get started with class tracking in QuickBooks Online
• Create and manage classes in QuickBooks Online.

Keep me posted if you have further concerns with changing the department for your invoice in QuickBooks. I'll be around to help. Stay safe, and have a good one.