Could someone tell me if SuiteBilling/Recurring Invoices are a standard feature available in NetSuite? I have an administrator account, and I'm going through the training on SuiteBilling, but I don't have the features to enable that they are enabling in Setup > Company > Enable Features or in Setup > Company > Accounting > Accounting Preferences

They are not free, Suitebilling aka Monexa is a paid addon, they changed the to Suitebilling when NS bought Monexa couple of years ago. As far as I know this is a premium module like Suitepeople, ARM, WMS etc.