Which task must a user perform by using the AWS account root user credentials?

Changing AWS Support plans is a task that must be performed by using the AWS account root user credentials. The root user is the email address that you used to sign up for AWS. It has complete access to all AWS services and resources in the account. You should use the root user only to perform a few account and service management tasks, such as changing AWS Support plans, closing the account, or changing the account name or email address. Making changes to AWS production resources, accessing AWS Cost and Usage Reports, and granting auditors access to an AWS account for a compliance audit are tasks that can be performed by using IAM users or roles, which are entities that you create in AWS to delegate permissions to access AWS services and resources.