See the following from About the upcoming changes with iTunes on Mac - Apple Support
New apps, same library
macOS Catalina makes it faster and simpler to access all of your “ripped” or imported music, purchased media, and more. The new apps organize your media just like the same apps on iOS. Your entire media collection will find a new home and transition automatically into the new Apple Music, Apple TV, and Apple Podcasts apps. In addition, your previous iTunes Store purchases and synced libraries will not change on any of your devices.