You can now assign custom attributes, or tags, to the AWS accounts you manage with AWS Organizations. The ability to attach tags such as owner name, project, business group, cost center, environment, and other values directly to your AWS accounts makes it easier for the people in your organization to get information on particular AWS accounts without having to refer to a separate spreadsheet or other out-of-band method for tracking your AWS accounts.
AWS Organizations helps you centrally govern your environment as you grow and scale your workloads on AWS. Using AWS Organizations, you can automate account creation, create groups of accounts to reflect your business needs, and apply policies for these groups for governance. You can also simplify billing by setting up a single payment method for all of your AWS accounts.
You can tag and untag AWS accounts using the AWS Organizations console or programmatically via the AWS SDK at no additional cost. For more information, please visit documentation on Tagging in AWS Organizations and read more about AWS Tagging Strategies.
from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/06/aws-organizations-now-supports-tagging-and-untagging-of-aws-acco/