Check the full post for some interesting integration scenarios
"Two years ago, we launched Outlook mobile with the goal of helping you accomplish more while on the go. More means an inbox that helps you focus on the emails that matter most. More means a calendar that can manage your entire day, not just show you your schedule. And today, we are excited to continue that mission by bringing apps to your inbox with add-ins for Outlook on iOS.Later in the post:
We’re thrilled to collaborate with Evernote, GIPHY, Nimble, Trello and Smartsheet and bring their add-ins to Outlook on iOS. We’re also making a few of our own add-ins available today with Dynamics 365 and Microsoft Translator, with many more to follow."
"Once enabled, you can access add-ins from Outlook on iOS as well as from Outlook 2016 or 2013 for Windows, Outlook on the web and Outlook 2016 for Mac (currently in Insiders) for the same email account.
Add-ins for Outlook on iOS are currently only available when reading email. We’ll be adding more add-in actions when composing or replying to an email in the future."Outlook mobile turns 2 and now comes with your favorite apps - Office Blogs