When using POP3 to download the mail, how to reserve the mail on server?

1. In the menubar, choose “Tools” and double click “Account Settings…”
 
2. In “Advanced” (If the version of Outlook is 2003 above, please choose particular email and click “Change” button, click “More setting”, and choose “Advanced”), user choose “Leave a copy of messages on the server”, also user can choose the number of day to remove the email from server.

 
Desktop version