Mail always downloads media attachments (such as image, PDF, video, or audio files) that you receive. They also appear in the From pop-up menu when you write a new message. If you already use aliases, they’re listed in the Email Address pop-up menu. If you want to change the name that’s shown in your messages, or create an email alias, click the Email Address pop-menu, then choose Edit Email Addresses. For an Exchange account, it’s the primary email address for the account on the Exchange server. The email address you want to use for sending messages. This name appears in Mail-for example, in the sidebar. Indicates if the account is online (a green dot) or offline (a red dot). When you disable an account (make it inactive), it’s taken offline the account’s mailboxes and messages don’t appear in Mail.