That says unsigned artists must register with one of those four services. From their web page, the first one listed (https://www.recordunion.com/ https://www.

That says unsigned artists must register with one of those four services. From their web page, the first one listed (https://www.recordunion.com/ https://www.recordunion.com/) is a digital distribution company that charges under $15/year to interface with an online store on the artist's behalf. If an artist is signed to a label then it's on the label to have a working relationship with the online stores and streaming services.