How do I add the "class" field when I run a journal report?

Thank you for reaching out to the Community, @kv230. I'll be happy to guide you further to enable you to assign Class fields in your Journal Report when creating an expense in QuickBooks Online (QBO). 

We can customize the Journal report to include the Class column. What you're going to want to do is set up class tracking, set up categories for expenses and accounts, and filter/sort total reports by class. This will make it easier to generate reports. 

Here’s how you can turn on the class tracking feature:

1. Click the Gear icon and select Account and Settings.
2. Tap the Advanced tab and click anywhere in the Categories section.
3. Toggle on the Track classes. Then, mark checks the Warn me when a transaction isn’t assigned a class. 
4. Under the Assign classes dropdown, choose the One for each row in the transaction. 
5. Press Save and Done.

Once done, try opening the same report again, and customize your Journal Report to show the Class column. Here's how: 

1. Go to the Reports tab and open the reports you want to pull up
2. Select Customize at the upper right. You'll see a lot of options for how you want to customize your report.
3. Under Rows/Columns, click Change columns. 
4. Select the Class checkbox. 
5. After customizing your report you can click Save customization. Ensure that the details you customize are saved and it'll be easy for you to access them in the future.

The customized reports that have been saved will go to the Customs page. You'll see the list of reports you've customized. 

To learn more about this one, see the Customise reports in the QuickBooks Online article. Feel free to visit our Reports page for more insights about managing your financial reports in QuickBooks. 

I'll be here if you need any other clarification about reports in QuickBooks Online. I'll get back to you as soon as possible. Have a good one!