The S3 repository plugin adds support for using S3 as a repository for Snapshot/Restore.
If you are looking for a hosted solution of Elasticsearch on AWS, please visit http://www.elastic.co/cloud.
Version 6.4.0 of the Elastic Stack has not yet been released.
The plugin can be removed with the following command:
sudo bin/elasticsearch-plugin remove repository-s3
The node must be stopped before removing the plugin.