Internet Radio

Works exactly the same as a conventional radio.
You select a station and listen to what is broadcasted.
The difference is that as it is internet, there is no limitation in distance.
You can listen to stations anywhere in the world.
Often there is a legal limitation, copyright.
This might prevent access often based on geo IP.

In general a compressed audio format is used.

Over time the bit rate increased.

Internet radio stations can accessed using your browser.

There are many standalone internet radio players.

Internet radio - Wikipedia