Locate the Mail Sidebar
Mailboxes are listed in the Mail app sidebar, which makes them easily accessible with just a click. If you don’t see the sidebar, go to View > Show Mailbox List or use the keyboard shortcut Shift+Command+M.
How to Create a New Mailbox
You can create as many mailboxes as you need, including mailboxes for individuals, groups, companies, or categories—anything that makes sense to you. To make a new mailbox:
How to Create Mailboxes Within Mailboxes
You may want to create mailboxes within mailboxes to further organize your email. For example, if you receive a lot of email newsletters, you might create a mailbox called Newsletters and within it create individual mailboxes for each newsletter or newsletter category. Similarly, you could set up a mailbox for Family and create individual mailboxes inside for each family member.
Move Existing Messages to a New Mailbox
To move existing messages to a new mailbox, 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 and release the mouse button. After you create mailboxes, you can use rules to file the incoming email automatically in the appropriate mailboxes to save time and stay organized. You can also create Smart Mailboxes to make it easier to find messages.