Let us look into two key concepts in IAM: Identities and roles. 

IAM Identities 
● An IAM identity is an AWS account or service that is granted permission to access AWS resources. 
● IAM identities can be either users or roles. 
● Users are IAM identities that represent people or processes that need access to AWS resources. 
● Users can be created and managed within your AWS account, and you can use IAM permissions to allow or deny access to specific resources or actions.

● Roles are IAM identities that are assumed by AWS services or external users. Roles are typically used to delegate access to AWS resources to other accounts or applications. For example, you might create a role that allows another account to access specific resources in your account. 

IAM Roles 
● An IAM role is a set of permissions that determines what actions an IAM identity can perform on AWS resources. 
● Roles can be created and managed within your AWS account, and you can use IAM permissions to allow or deny access to specific resources or actions. 

There are two types of IAM roles: 
1. AWS service roles: These roles are used by AWS services to access resources in your account. For example, an Amazon EC2 instance might assume a role to access an Amazon S3 bucket. 
2. Custom roles: These roles are created by you and can be assumed by AWS services or external users. Custom roles are typically used to delegate access to AWS resources to other accounts or applications. 
Understanding how identities and roles work in IAM is important for effectively securing your resources and data in the cloud. 
Use cases for IAM roles 

IAM roles are commonly used in the following scenarios:
● Delegating access to AWS resources: You can use IAM roles to grant access to AWS resources to other accounts or applications. For example, you might create a role that allows another account to access specific resources in your account. 
● Allowing AWS services to access resources: You can use IAM roles to allow AWS services to access resources in your account. For example, an Amazon EC2 instance might assume a role to access an Amazon S3 bucket. 
● Granting access to third-party applications: You can use IAM roles to grant access to AWS resources to third-party applications. For example, you might create a role that allows a third-party application to access your Amazon S3 buckets. 

Creating IAM roles 
To create an IAM role, you will need to perform the following steps: 1. Sign in to the AWS Management Console. 
2. Navigate to the IAM console. 
3. Click on the "Roles" menu in the left-hand navigation. 
4. Click the "Create role" button. 
5. Select the role type. There are two types of IAM roles: AWS service roles and custom roles. 
6. Select the AWS service or external user that will assume the role. 7. Attach permissions policies to the role. These policies determine what actions the role can perform on AWS resources. 
8. Review the role and click "Create role" to create the role. 
9. Once you have created an IAM role, you can use it to grant permissions to AWS resources.You can also attach or detach permissions policies to the role as needed to allow or deny access to specific resources or actions.