Yes, there's a feature that you'll need to upgrade, @anunesdmd.
I agreed with Fiat Lux - ASIA that class tracking is only available in QuickBooks Online Plus and Advanced versions. If you want to upgrade, you can follow the steps below. But before upgrading, you'll want to check the different features in QBO to know what version fits your business. Please go to this link and proceed to FAQ: https://quickbooks.intuit.com/global/online-compare/.
Once you have the mentioned versions, you can now turn on the class tracking to start immediately by going to the Account and Settings. Next isto choose the Advanced button, then under Categories, click the radio button beside Track classes.