In-tray holds documents that come from people who do not share any folders with you (yet). You decide whether to accept the files or to reject them. If you accept the files, their senders will be able to continue sending you documents (using your mydocsafe.com email address). If you reject them, any subsequent files from those senders will be ignored. You can always change our mind later by going to Account Settings. In-tray is always the topmost folder on your home screen.