To grant admin privileges to a user, select that user in User management and click Administration privileges.
Any user granted ALL administration privileges becomes a de facto Account Owner.
Below is more information about the administration privileges:
Manage applications - Rights to create and delete applications and portfolios, as well as to modify any aspect of the application configuration (model, portfolio, audit, etc). See Applications management.
Manage users - Rights to create, delete and manage users, user groups and roles, as well as to assign permissions among them. See User management.
Manage models - Rights to create and delete custom models, as well as to modify any aspect of model configuration (rules, indicators, metrics, etc.) See Models Manager User Guide.
Manage audits - Rights to create and delete custom audits, as well as to modify any aspect of the audit configuration (checkpoints, etc.) See Audits Management.
Manage reports - Rights to create and delete custom reports, as well as to modify any aspect of the reports (contents, widgets, etc.) See Custom Reports.