Apple released macOS Catalina 10.15 beta 7 to developers today. The build number is 19A546d.
Run the macOS Developer Beta Access Utility to download the latest macOS beta. As new macOS betas become available you will receive a notification and can install them from the Software Update pane in System Preferences.
With macOS Catalina, Apple is replacing iTunes with new Apple Music, Apple Podcasts and Apple TV apps. A new Sidecar feature enables users to extend their Mac desktop by using their iPad as a second display or as a high-precision input device.
New security features keep users better protected and Voice Control lets users control their Mac entirely with their voice. You can learn more about macOS Catalina here.
Developers can download the Beta Access Utility from the link below.