Governance covers below areas - 

• What type of decisions
• Who has the authority to make them
• What is the process of making them

Governance can be breakdown into three below areas-

Data governance - ServiceNow data governance defines the standards and practices for owning and managing
data assets created, stored, and/or processed on the Now Platform. It’s a key part of
ServiceNow technical governance, so be sure to develop and/or approve it in collaboration
with your ServiceNow technical governance board. 

ServiceNow environment governance defines the standards and practices for how to right-size
environments, replicate instances correctly, and ensure proper ServiceNow environment
maintenance

More importantly, there should be methods for continuously improve governance like defining metrics, removing bottlenecks and triage decisions.