Let's start with Automation. You can have the "Personal" Focus profile activate automatically, so you never need to enable it yourself. First, tap the settings box under "Turn On Automatically," then choose whether you want Focus to enable at a certain "Time," "Location," or with an "App." Now, choose the on-screen controls for your given option, then tap "Done."
You can also choose "Smart Activation," which takes these controls into its own hands — no manual settings needed.
Finally, turn your attention to "Options." Here, you can choose whether "Personal" Focus dims the lock screen, whether notifications not in your approved list are sent silently to Notification Center under "Delayed Delivery," and whether or not to hide notification badges with "Hide Notification Badges."
Note: Apple's iOS 15 is currently in beta development. A public beta will be available in July, while the final release isn't expected until the fall of 2021. Anything shown in this guide may change or be removed during the development cycle.