The new app is basically a replacement for San Francisco-based email startup Acompli that was acquired by Microsoft for $200 million in December last year, New York Daily News reported.
Outlook will support Office 365, Exchange, Outlook.com, Yahoo Mail, Gmail, iCloud and other key email services.
The app will also help users manage calendar and fetch attachments within the same app.
Users will be able to attach files from Dropbox, Google Drive, Microsoft OneDrive or the user's mailbox right from the app.
"Our mission is to bring the best mobile email experience across platforms, in a way that is as familiar and functional as Outlook itself," Javier Soltero, Outlook general manager and former CEO of Acompli said in a statement.
The new Outlook app will be a similar experience to the Acompli.
Microsoft also announced that it is removing the "preview" tag from its Office suite for Android apps.