Hi @Mark Y, thanks for joining the Community!
Dropbox is a service that allows you to store and sync files to and from the site and other connected devices. Other features, such as sharing, automation, backups and so on are also included.
We do have a section of the site which can help you to set up your account, and educate users on the main features of the service.
If you have any further queries, feel free to message back.