In Discord you can create servers and chat with your friends in rooms. You can create roles, ban members, kick members in your discord server. Like i said you can develop your own bot too but I am not going to tell how to do it because it is long. If you don't know to code a bot Discord has prepared bots too, you can add them to your server and use them as perfect tools! If you don't want to chat in a server you can chat with your friends in DM. You can create groups too in DM but there aren't any roles or bots allowed. It is just a private conversation. If you want to chat in private in a server you can change the permissions of the channel and make it spesific roles can see it. You can even color de roles. That is pretty much what you can use Discord for.