Microsoft Outlook for iOS is a free email app which brings together not only your emails but calendars and contacts from all accounts.
To make things as straightforward as possible, it works with Microsoft Exchange, Office 365, Outlook.com, iCloud, Yahoo, and Gmail, and enables you to attach files directly from your email, OneDrive or Dropbox.
Outlook for iOS helps keep managing your email as easy as possible. You can quickly filter mail to find unread items and locate attachments, in a few taps or by using a couple of letters. Deleting unwanted mail just takes a quick swipe, or you can schedule emails and theythey can be processed at a later date.