Governance consists of key functions that control your business such as tools and technology, communication, contracting / legal, and financial processes and indicators.
People refers to the talent you have in your organization and the infrastructure you use to support them throughout the lifecycle - from attracting, hiring, and retaining the right employees, to development (training, coaching and advising) and career pathing.
Service Execution encompasses the end to end process of delivering the services or products you provide including methodology, infrastructure, and customer satisfaction.
Go To Market is everything related to what services / products you provide and how you get your offerings out there (sales & marketing)