You should always claim your artist profile on the platforms whenever you start.
For Spotify you can go to https://artists.spotify.com/
For Apple Music and iTunes visit: https://artists.apple.com/
For Deezer you can change details at: https://creators.deezer.com/
For Tidal you can go to: https://artists.tidal.com/
For Amazon Music checkout: https://artists.amazon.com/select
For Beatport fill out the form found here.
How do I get an official artist channel on YouTube?
Simply sign up with an account on YouTube and try to get your artistname as a channel.
Please note that currently it will take YouTube a couple of months to perform quality assurance and then upgrade the channel to an OAC.
More information can be found in this document.