Get the details from http://docs.oracle.com/cd/E24628_01/doc.121/e25353.pdf

■Framework and Infrastructure
–Updated Management Repository Page
–Enterprise Manager Page Performance Page
–Incident Management Actions in System Dashboard
–BI Publisher Integration
–Integrated Installation of Business Information Publisher with Enterprise Manager 12c
–Security Console
–SSH Key Credential Support in Preferred Credentials
–Global Preferred Credentials
–Private Roles
–Default and Bulk Apply Privilege Delegation Template
–Fine Grained Aggregate Target Type Privilege Enhancement
–Job System Enhancements
–Enhanced Customization of Patching Procedures
–Agent-Side Check Based Rule and Secure Technical Implementation Guide Compliance
–Plug-in Management
■Services Management
–New Create Wizard for Services
–Support for REST and WADL for Web Service Beacon Tests
■Enterprise Monitoring and Incident Management Features
–Advanced Thresholds Management
–Metric Alert Message Customization
–Metric Collection Schedule Enhancements
–Time-Based Static Thresholds
–Repository-Side Metric Extensions
Framework and Infrastructure
New Features In Oracle Enterprise Manager Cloud Control 12c 2-3
–Metrics Enhancements
–Incident Management Updates in
–Notification Enhancements
–Enhanced Target Down Detection
■Fusion Application Management Features
–Oracle Fusion Applications Plug-in Features
■Database Management Features
–Database Plug-in Features
■Middleware Management Features
–Fusion Middleware Plug-in Features
■Exadata Features
–Exadata Plug-in
–Exadata Plug-in
■Cloud Management Features
–Cloud Management Plug-in Features
–Chargeback and Consolidation Planner Plug-in Features
–Virtual Infrastructure Plug-in
–Cloud Framework Plug-in
■Lifecycle Management
–Scheduling Patch Preparation, Deployment, and Switchback