Open the Settings app
Tap Music
Turn off Sync Library
Confirm when prompted
On Mac, open the Music app
Choose Music from the menu bar
Click Settings or Preferences
Go to the General tab
Uncheck Sync Library
Click OK or Done
On Windows, open iTunes
Click Edit
Select Preferences
Open the General tab
Uncheck iCloud Music Library or Sync Library
Click OK
If needed, sign out of Apple Music or iTunes Store
Restart the device if the change does not appear immediately