Like most media these days, Daria can be viewed via streaming. Currently, it is available for streaming at Paramount+.
Fans (and randos) have been illicitly uploading episodes to YouTube for about as long as YouTube has been around. These are typically removed by the show's rights holders. As the Wiki does not officially condone media piracy, we won't be offering any links to this kind of thing.
One of MTV's official YouTube channels did carry a handful of Daria episodes for a short while in late 2015 and early 2016. These were eventually removed.
The streaming service Hulu answered the prayers of many fans by making Daria available to subscribers. Or almost all of Daria, anyway--the movies, Is It Fall Yet? and Is It College Yet? were not included. The streamed versions also used the generic filler music heard in the DVD episodes, presumably since this simplified the rights issues.
Hulu removed Daria on June 20th, 2020.
Picking up where Hulu left off, Paramount+ (previously named CBS All Access) began showing Daria later in 2020. As is the case with Hulu, Paramount+ did not include the movies or the original music.
As of 2020, Daria is available to stream on Amazon's Prime Video - though you have to pay for it.
Jodie was picked up by Comedy Central. When the show is made, it will presumably be streamed on Comedy Central's website.