You can do this by enabling first the class tracking feature through a web browser, Scotts1769. Here's how:
- Sign in to the QuickBooks Online web browser using your credentials.
- Go to the Gear icon, then click Account and Settings.
- Select Advanced, then choose Categories.
- Tap Track classes to turn it on.
- Select an option from the Assigned classes dropdown:
- If you don’t need to assign a class to each product you sell to your customer, select One for the entire transaction.
- If you need to assign a class to each product you sell to your customer, choose One for each row in a transaction.
- Then, hit Save.
Then, sign back into your iPhone mobile app and tap the Expense button. On the Expense page, swipe down and click the Class arrow to add it. Please refer to the sample screenshot.

For comprehensive guidance on enabling the class feature, as well as creating and assigning classes, please refer to this article: Turn on class tracking in QuickBooks Online.
When you need to review a report on transactions tracked by class, select Profit and Loss by Class and refer to this article for details: Run a Profit & Loss report using the app (iOS only).
Whenever you still need assistance with other task or guidance on what to do next, feel free to collaborate with our QuickBooks Live Expert Assisted Team. These specialized professionals can help you with anything you need for your business.
We're here to help whenever you need further support with tracking your transactions. Please click the Reply button below to submit your inquiries.