There are two main types of users in AWS:
Root user: The root user is the most powerful user in an AWS account. The root user has full access to all AWS resources and services.
IAM users: IAM users are users that you create in AWS. IAM users can be granted specific permissions to access and use AWS resources and services.
Businesses can aptly assign the type of AWS users based on their specific requirements during the conduction of Well-Architected Review AWS.