Are you tired of seeing all the Happy Birthday notifications on your Windows 10 Start Screen? People, you don't even know.
Open the Calendar app on your Windows 10. You can search (using WIN+S) and type Calendar and load the Calendar app. You will see all the many birthdays.
Go to the left side menu bar and look for a check box "Birthday calendar" and uncheck it.
You will then see all the reminders are gone!