Apple Music has its own platform Apple Music for Artists who have music live on the platform. All you need is music live on the service, Facebook/Twitter accounts and contact details ready. For independent artists, you should put your own details for Label/distribution contact and management contract when signing up.
You can edit your artist image via the platform. Please ensure it’s 2400x2400 and all key elements (i.e. artist's faces) are centralized, as the image will be cropped into a circle. The image needs to be a clear representation of the artist, images that are too dark for example will be refused.