Yes and no: adding a column? Sure. Displaying comments/notes users entered somewhere else and have been stored in a source and modelled accordingly with the business models? Yes.
Adding a column where users add comments directly and save them in OBIEE isn't an out of the box feature.
You would need a 3rd party tool like OBIEE Commenting & Annotation Tool | Collaborate with BITeamwork or https://www.rittmanmead.com/chitchat/ .
Writeback would be a super simplistic way to add comments, an APEX form would be a more powerful way.
All in all: you either need an extra tool or to code things and it will not be as simple as you hope it would be
Thank you Gianni