There are two ways that you can support artists via Spotify:
1. Play their music via one of the streaming platforms. Artists receive a small amount of money for each time a song is streamed. This doesn't cost you extra, and at the same time helps the artist. Play your favorite playlists as much as possible (you're helping even if the volume is very low...)
2. Donate directly to an artist...
As of April 22nd, Spotify for Artists has added a new feature called: the Artist Fundraising Pick. Artists can highlight a fundraising destination on their profile as an Artist’s Pick (in addition to their Artist’s Pick).
First and foremost, this feature enables artists who are interested in raising money to support themselves, their bands, or their crews, to get the word out to their fans on their Spotify artist profiles. Spotify has engaged a strong group of initial fundraising partners: Artists can choose to add a link to Cash App, GoFundMe, and PayPal.me.
If you are an Artist, then consider enabling the Artist Fundraising Pick on Spotify so that your fans can donate directly. (https://artists.spotify.com/blog/introducing-artist-fundraising-pick)
If you are a listener, play the music that you love via the streaming platforms (Spotify has the highest Artist-payouts), and consider making a donation using the Fundraising link on the Artist's profile on Spotify (if he/she has enabled it).