How to set up and use a Focus on iPhone and iPad
Tap Allow Time Sensitive notifications if you want people and apps to deliver important notifications immediately, even when Focus is on. Thats all there is to getting a Focus set up. If you decide you want to add or remove people and apps from a Focus, you can do so at any time. Now that you have a Focus set up, its time to dig even further with customizations. How to customize the Home Screen in Focus Once you have a Focus set up, you can even choose a custom Home Screen to go along with it....
Source: imore.com