How to make the notes above/below your reply in a thread

The notes you can write above/below the main body of your reply on a thread that has the thick vertical line beside it. How do I do that? Not sure if there was a certain code to use or..? ?

the code is (ooc)(/ooc) but...with [] instead of (). 

you can also select a piece of text and under styles, choose ooc text.

There is also the MyCode database in the Guidebook:
https://wolf-rpg.com/showthread.php?tid=8406