We released a new update today, which you can install by clicking File > Account > Update Options > Update Now.
In this build, look for a new feedback icon in the upper-right corner of your Office 2016 apps:
As you may recall, you can already submit feedback from inside any app by clicking File > Feedback, but only if you’re running Office 2016 on Windows 10. The Send a Smile and Send a Frown commands appear in Office Insider builds, no matter which version of Windows you’re using. We encourage you make good use of them, since as you know, we are fond of all Insider feedback, be it good or bad.
The Office Insider Team