Sign in with your Apple ID in Music on Mac
To subscribe to Apple Music or buy items in the iTunes Store, you need an Apple ID. If you don’t have one, you can set one up using Music. You already have an Apple ID if you subscribed to Apple Music or have an iCloud account.
Set up a new Apple ID in the Music app
In the Music app on your Mac, choose Account > Sign In.
Click Create Apple ID and follow the onscreen instructions.
Sign in to or out of the Music app
After you set up an Apple ID, you can sign in to the iTunes Store to buy music, view or change your account information and display your purchase history.
Note: If you already signed in to Podcasts or the Apple TV app, you’re automatically signed in to Music.
In the Music app on your Mac, choose Account > Sign In (or Sign Out).
If you forgot your Apple ID or password, click Forgot Apple ID or Password? and follow the on-screen instructions.