There are two editions of Docker: Community Edition (CE) and Enterprise Edition (EE). Docker Enterprise Edition is not supported for use with Enterprise Server so you must install Docker Community Edition.
You must obtain Docker Community Edition for Red Hat Linux or SUSE Linux from your operating system provider rather than from Docker.
For full information on installing Docker on Red Hat Enterprise Linux see Red Hat: Getting Started with Containers.
For full information on installing Docker on SUSE Linux Enterprise Server see SUSE: Docker Guide.
On Ubuntu, in order for debugging to work within a Docker version 18.04 Container, you must update the kernel of the Docker host from version 5.0.0-27 to 5.0.0-31.
Before installing the required third-party software, see Container Known Issues and Restrictions for information that might be relevant to your use of containers.