The name of a P&L by class in QBO is just Profit and Loss by Class. If you're not seeing an option to run this report it is because your class tracking in QBO is turn off. To be able to run this report you need to turn on the class tracking feature.
To turn on class tracking feature, here's how:
Click the Gear icon, then Accounts and Settings.
Go to the Advanced tab, then Categories.
Click on Track classes or the pencil icon to turn it on.
Click Save once done.
Go back to the Reports tab and you will now have the Profit and Loss by Class option.