As an Office 365 Global Admin I has the highest level of role in a Microsoft 365 tenant.
I can manage all services, users, licenses, security settings, organizational configurations, security and compliance features, Exchange, SharePoint, Teams, and Azure AD settings.
I can configure organization-wide policies, and handle critical tasks like domain management and data governance. Because it provides unrestricted control, the role is usually given to only a few trusted individuals for security reasons.