Autofill suggested contacts - Exchange

[Mitul Patel1]

I have a galaxy s4 mini. I don't keep everyone's contact info in my exchange contacts and like when outlook autofills email addresses for me. How do I activate this on my phone? When I'm on the go and want to email someone for which I do not have them stored but know the first few letters of their email... just like in Outlook. Any suggestions?