An outbox is a designated folder in an email client where messages that have been sent but havent yet been delivered are stored. When you hit "send" on an email, it goes through several stages before reaching its destination. The email is moved from your drafts or composition area to the outbox, where it waits for delivery to be processed. The email client then connects to the mail server, which attempts to deliver the message to the recipients email server. If successful, the email leaves the outbox and is marked as sent. If there is an issue with delivery, the message will stay in your outbox until the problem is fixed. For example, if youre offline or theres an issue with the server, your email will stay in the outbox until the issue is resolved and the connection is re-established. The outbox is important because it stores messages that havent been sent yet, ensuring that they are not lost if there are connectivity issues or if the recipient is currently offline.