You can host a server on your own computer by downloading utorrent, creating a minecraft world, opening to lan and placing the port the world save gives you into preferences->connection->port used for incoming connections.
the server is then available for other players to join while you are playing and the server ip is: Your IP:The port i.e xx.xx.xxx.xxx:xxxxx
additionally you can get a free server here, but expect latency in activating it and it automatically shutting down after 5 min of inactivity. additionally, expect it to lag if a lot of players get online. https://aternos.org/:en/
