AWS Certificate Manager Private Certificate Authority now supports Private CA sharing
AWS Certificate Manager (ACM) Private Certificate Authority (CA) now supports sharing a Private CA with any AWS account or within your organization. Customers manage a Private CA in a central account and use AWS Resource Access Manager (RAM) to share the CA with other accounts or organizations where SSL/TLS certificates will be issued. This eliminates the need to provision duplicate resources in every account in a multi-account environment, reducing the cost and complexity of managing those resources in every account.
Source:: Amazon AWS