Adds one or more tags to your private CA. Tags are labels that you can use to identify and organize your Amazon Web Services resources. Each tag consists of a key and an optional value. You specify the private CA on input by its Amazon Resource Name (ARN). You specify the tag by using a key-value pair. You can apply a tag to just one private CA if you want to identify a specific characteristic of that CA, or you can apply the same tag to multiple private CAs if you want to filter for a common relationship among those CAs. To remove one or more tags, use the UntagCertificateAuthority action. Call the ListTags action to see what tags are associated with your CA.