For example, IF you're using Microsoft Outlook on the desktop, then the setting you're looking for resides in the location mentioned in the link below.. (Although the link discusses UNCHECKING the box for "Leave Messages on Server", you will want to do the opposite.. You'll want to CHECK the box.)
Hope this helps.
I have a desktop and a laptop. I want to leave email msgs on my the ISP server for my laptop so that I have a backup on the desktop. I know it can be done, but it's been so long since I did it for my last laptop (which crashed) I can't seem to find the proper menu again. Help would be appreciated. Thanx