Note that you may only customize your notifications on your mobile device:
On mobile, go to your profile.
Click the settings icon on the top right corner.
Click on which notification you'd like to modify.
Select how you'd like to be notified: Email notifications or push notifications.
If you want to be notified via both email and push notifications, you can select both options.
For circle notifications, you can change how often and what type of notifications you want to see in each circle.