Office Insider update for iOS and Android brings support for comments and @mentions. Microsoft is bringing @mentions support for PowerPoint, Word, and Excel.
Get their attention with @mentions (Word and PowerPoint)
Use @mentions in comments to let co-workers know when you need their input.
Collaborate effectively with comments and @mentions (Excel)
Keep the conversation going right in your worksheet with the built-in reply box and let co-workers know that you need their input by using @mentions.