You will see the list of e-mails sent by all the users that were delivered, for the current day and specified domain.
View dropdown: alter your search criteria and filter out by Temporarily Rejected messages (user is over quota, for example), Permanently Rejected messages (invalid mailbox, blacklisted, etc.), or All Messages.
Sent To: specify the email address where you sent the message (or part of an email address). This field is optional.
Sent From: specify the individual e-mail address to search for as having sent the messages. This field is optional.