It can be really distracting to get notifications from the Mail or the Message App while you are trying to focus on work and trying to get something done. However, you can focus on certain active apps that appear to bother you quite often with Alerts or banners and change their notification behaviour or totally disable notifications from such active apps. Hence, there is no way to disable or change the notification style for all the Apps at once on your Mac. Unfortunately, there is no global setting for notifications on Mac.
