Which service would you use to simplify account management across multiple AWS accounts?

Using AWS Organizations is the best option for simplifying account management across multiple AWS accounts. This service enables you to manage multiple AWS accounts centrally, allowing you to create and manage accounts programmatically, apply policies, and define governance models for your organization. With AWS Organizations, you can set up a hierarchical structure that reflects your organization's needs, allowing for efficient management of billing, access control, and resource sharing among accounts.

AWS Control Tower is often used to establish and govern a secure and compliant multi-account AWS environment, but it builds upon the functionality of AWS Organizations. While it provides a more guided setup and governance capabilities, it still relies on AWS Organizations for the foundational account management.

AWS Identity Center provides a way to manage user access across AWS accounts but does not focus on the centralized management of accounts themselves. It can work in conjunction with AWS Organizations but is not specifically designed to manage the accounts.

The AWS Management Console is the web-based user interface for managing AWS services but does not provide specific features aimed at simplifying account management across multiple accounts. It allows users to interact with AWS resources, but it is not an account management service.

Therefore, using AWS Organizations is essential for efficiently managing multiple accounts within an organization, making it the appropriate choice in this context.