You can leverage discussions to collaborate with your team. You can have discussions that are private or open to everyone in your team. All the discussions that were initiated on a given part or a document can be accessed easily at a later point. You can also include markups created on a 3D design to discuss design changes or provide design direction.
You can access the discussion via: Home Page
or via dedicated discussions page
Alternately, you can locate the part or the document and then open the discussions panel