How To Organize Your Apple Mail With Mailboxes - Mailboxes listed in the mail sidebar is an easy ways to keep your email in it folders under control. Mailboxes also give users advantage by organize user email in their inbox or piled into one or two mailboxes. So users can create many mailboxes as they want such as by category, individuals, groups ot others.
Select New Mailbox from the Mailbox menu, or click the plus (+) sign at the bottom left of the Mail window and select New Mailbox from the pop-up menu. In the Name field, type Newsletters and click OK.
To create a sub-folder for About: Macs newsletters, click once on the Newsletters mailbox. Select New Mailbox from the Mailbox menu, or click the plus (+) sign at the bottom left of the Mail window and select New Mailbox from the pop-up menu. In the Name field, type About Macs and click OK.
Click and drag the messages to the target mailbox. You can also move messages by right-clicking on a message or group of messages and selecting Move To from the pop-up menu. Select the appropriate mailbox from the pop-up menu and release the mouse button.
You can also move existing messages to new mailboxes by creating and applying rules.