You can organize saved messages into a filing cabinet.

One of the easiest ways to use your filing cabinet is to use what Outlook calls the Folder List:

1. If you don't see the folder list next to your message listings, you need to turn it on. Choose Folder List from the View menu.
2. With the folder list visible, look for the Cabinet entry. If there is a tiny plus (+) sign next to it, your file cabinet is currently closed. Open it by clicking on that plus (+) sign. It will change to a minus (-) sign and show the folders, if any, in the cabinet.
3. You can drag messages to your cabinet's folders, or click on a folder name to view its contents.
4. You can create new folders in your filing cabinet by first highlighting the Cabinet entry and then opening the File menu and choosing New and then Folder. Be sure to pay attention to where you tell Outlook to place that folder - put it in your filing cabinet, not your inbox or elsewhere.
5. Whenever you want to go back to your usual mailbox view, click on the Inbox shortcut or the Inbox entry in your folder list.