To determine the correct statement about the "Outbox" in the context of email services, let's analyze each provided option:

1. "It is used to receive incoming emails."
   This statement refers to the "Inbox," which is the folder dedicated to receiving incoming emails from different senders. Thus, this option is incorrect regarding the "Outbox."

2. "It holds emails that have been successfully sent."
   Once an email is successfully sent, it is typically moved to the "Sent" folder. The "Outbox" is used for a different purpose before this stage. Therefore, this option is incorrect.

3. "It temporarily stores emails that are queued for sending."
   The "Outbox" serves as the temporary holding area for emails that are in the process of being sent. If there is an issue with connectivity, these emails remain in the Outbox until they can be sent successfully. This statement correctly describes the purpose of the Outbox.

4. "It contains emails that are currently being drafted."
   Emails that are being written or drafted are saved in the "Drafts" folder, not the Outbox. Thus, this option is incorrect for the Outbox context.

Conclusion: The correct statement about the Outbox is that it "temporarily stores emails that are queued for sending." This accurately describes the function of the Outbox in email services.