Setting Exchange up so that it keeps a copy of a users email

What I mean by that is how do I set Exchange up so that if I have a laptop and a workstation at the office and I get on my lappy and retrieve my mail the mail will still be there so that when I get to my office I can get the same email on my workstation.

I googled this but didn’t find exactly what I was looking for.

Thanks in advance,

Daniel