A company has an organization in AWS Organizations that includes dedicated accounts for each of...

To allow an IAM user in one AWS account to access resources in another AWS account using IAM roles, the following steps are required:

Create a role in the AWS account that contains the resources (the trusting account) and specify the AWS account that contains the IAM user (the trusted account) as a trusted entity in the role’s trust policy. This allows users from the trusted account to assume the role and access resources in the trusting account.

Attach a policy to the IAM user in the trusted account that allows the user to assume the role in the trusting account. The policy must specify the ARN of the role that was created in the trusting account.

The IAM user can then switch roles or use temporary credentials to access the resources in the trusting account.

Verified References:

https://repost.aws/knowledge-center/cross-account-access-iam

https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_accounts_access.html

https://docs.aws.amazon.com/IAM/latest/UserGuide/tutorial_cross-account-with-roles.html