As I said in my previous blog, at OOW2016 Oracle made clear statement - "the latest release Oracle 12.2 was officially announced to be first made available in the cloud. " The first available platform is Exadata Express Cloud Service.With this service, the customer can get Oracle Database 12c Release 2 Enterprise Edition plus options running on Exadata in Oracle Cloud.
If you have neither joined Oracle 12.2 beta program nor used Exadata Express Cloud Service, you can at least learn about Oracle 12.2.
Here are some publicly available documents from Oracle:
Database 12.2 New Features Guide – https://docs.oracle.com/cloud/latest/exadataexpress-cloud/CSDBF/toc.htm
Using Oracle Database Exadata Express Cloud Service – https://docs.oracle.com/cloud/latest/exadataexpress-cloud/CSDBP/toc.htm