Zimbra is NCF's webmail system.
About the Briefcase
The 'Briefcase' in Zimbra is a place that you can upload files, save attachments, and share with others.
You might use it to keep track of important documents, knowing that they'll be safe and secure even if your home computer crashes.
It can also be a great help when sharing files. Instead of sending out massive emails containing large photos to all your friends and family, only to have half of them bounce or encounter other problems - you simply upload the photos to a briefcase, and share that briefcase with your friends and family instead.