Your profile shows that you are using Office 2010 64 bit (32 bit is the preferred option for most users) however the illustration is from Word 2013?
You are showing comments in balloons, which is the default setting.
In Word 2013 > Review Tab > Tracking Group > Show Markup > Balloons > Check Show All Revisions In Line.
If you are commenting on the work of students, you may find
http://www.gmayor.com/insert_custom_comments.htm useful.