With iCloud, you get an email address at icloud.com and a mail inbox that’s always up to date. iCloud pushes new messages and email folder changes to each device you set up to work with iCloud.
For example, if you receive an email on your iPhone then file it in a folder, that email appears in the same folder on your other devices.
If you turn on Mail when you set up iCloud, you can:
View all your email, including the same inboxes and mail folders, on each of your devices (in Mail on your iOS devices, OS X Mail on your Mac, or Microsoft Outlook 2007 or 2010 on a Windows computer).
Manage and edit your mail from any computer using the ad-free iCloud Mail web application at icloud.com/mail.