Outlook determines what goes into a Search Folder based on whether a message satisfies certain conditions (for example, if the message hasn't yet been read, it is displayed automatically in the Unread Messages Search Folder). These conditions are the Search Folder's criteria (the characteristics of a message that will qualify it for display in the Search Folder).
Once you create a Search Folder, new messages will automatically appear in it if they meet the criteria of the folder—which means that, once you've created it, the folder will always keep itself up to date.
There are two ways to set up a Search Folder:
From the File menu If you set up your Search Folder from the File menu, you can choose from a number of predefined Search Folder options. This is the easier method by far for creating Search Folders, because Outlook prompts you for the criteria and then creates the Search Folder for you based on your choices.
From the Find Bar When you start with the Find Bar, you specify the criteria for a search and then click Find Now to find messages. After Outlook completes the search, you have the option to save the search criteria as a Search Folder.
Note You can also create a Search Folder from the Advanced Find dialog box by clicking Save as a Search Folder on the File menu of that dialog box.