Co-authoring on SharePoint 2013

Overview:  Co-authoring has been around awhile and I haven't paid it any attention in a long time.  The idea is multiple authors can edit the same document at the same time.  

Notes: 

1. Word and PowerPoint use to be the only supported files for co-authoring.  SharEPoint 2013 supports co-authoring in word 2013, PowerPoint, OneNote and visio 2013 as of 20April 2016.  
2. Excel does not provide co-authoring unless you use Office Web Apps or excel services.  More info
   

Article describes nicely what applications work with co-authoring  https://technet.microsoft.com/en-us/library/ff718249.aspx