Use StackSets to centrally manage deployments to all the accounts in your organization or specific organizational units (OUs) in AWS Organizations. You can enable automatic deployments to any new accounts added to your organization or OUs. The permissions needed to deploy across accounts will automatically be handled by StackSets. For more information, see Working with AWS CloudFormation StackSets.
The AWS CloudFormation stack import operation can import existing stacks into new or existing stack sets, so that you can migrate existing stacks to a stack set in one operation.