Explanation
On autonomous there's no patching needed. But on the regular DB Cloud services you need to patch the DB and the OS. During the creation on the OCDB the first DB is created automatically Oracle automatically takes care of Operating system Installation/Configuration, Grid Infrastructure, ASM diskgroup Creation/Configuration , and database software Installation and first database on the DB System.
that's all when Creating DB Systems. and then the customer responsible to apply the patches to the database and OS