What rights do I need to have to publish music?
If you are an author of music and lyrics and you'd like to release your song to digital stores, then no supporting documents are required. Copyright - the personal right of a person to be recognized as the author of the results of intellectual activity.
If you are a label and are not the author of the released music, then in order to release the tracks you need to have a signed license agreement with the authors of these tracks.