Microsoft will now let you collaborate on Word files stored on OneDrive using the desktop Office 2016 suite.
While real-time co-authoring has been available in for Office Online since 2013, Office 2016 will be the first traditional version of the productivity suite with real-time collaboration support.
If you and your teammate are currently previewing Office 2016, you can try it out by storing a Word document in OneDrive, and giving both users editing permission. Word will then prompt you to automatically share your changes.