How do i assign class to revenue and expense accounts that were set up prior to creation of classes? Can I do this with a journal entry?

Hi there, @userwrjnortheast.

In QuickBooks Online, you have the option to assign any class you want as this will remove to not specified area. It will depend on what kind of class you can enter or add.

Classes could be the different services you provide and the products that you sell. Let me share the steps on how to assign a class for each employee.

Here’s how:

1. Click on the Gear icon.
2. Select Payroll Settings.
3. Choose Accounting.
4. In the Classes section, select I use different classes for different employees.
5. Click on OK.
6. In the Preferences - Employee Classes section, assign a class for each employee. 
7. Click on OK.

Journal entries are used as the last resort for entering transactions. You also use this when you transfer money between income and expense accounts. Or, transfer money from asset, liability, or equity to any income and expense accounts. 

You're unable to change the class by creating entries. You'll have to open the transaction and change the class manually.

Then, when you pull up the Sales by Customer report, it will show the transaction's correct class. You can also customize the report to help you focus on the details that you want.

For more information about class tracking in QuickBooks Online, you may check this article:

•  How to set up and use class and location tracking.
• Get started with class tracking in QuickBooks Online.

If you have any other questions about this. I'll be keeping an eye out for your response. Keep safe always.

@userwrjnortheast 

You may utilize a migration tool as a workaround. Export the transaction out to XLS, put the class, and import them back into your QBO account.

https:// transactionpro.grsm.io/qbo