Find out more about the differences between Announcements and Notifications in Learn.
Announcements and notifications may seem similar, but in fact they are quite different. Notifications are emails generated by Learn automatically. You can change how often you receive them or switch them off entirely, this is illustrated in the video on the notifications page.
Announcements are written and sent by a member of staff in the course team. They are visible through the Announcements tool in Learn, but staff have the option to send an announcement as email too, in which case you will receive a copy of the announcement in your student email account. The email's sender will be the member of staff who wrote and sent the announcement.
Announcements are only emailed by staff when they feel the content is important and so you can't switch them off.