IAM identities are created to provide authentication for people and processes in your aws account.
IAM identities are categorized as given below:
AWS Account Root User
When you first create an AWS account, you create an account as a root user identity which is used to sign in to AWS.
You can sign to the AWS Management Console by entering your email address and password. The combination of email address and password is known as root user credentials.
When you sign in to AWS account as a root user, you have unrestricted access to all the resources in AWS account.
The Root user can also access the billing information as well as can change the password also.