In the rich text editor:
@CrizOstar
In a comment:
[CrizOstar](https://chowlings.com/user/CrizOstar)
For Names and Avatars:
In the rich text editor:
%CrizOstar
In a comment:
[![CrizOstar's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/CrizOstar) [CrizOstar](https://chowlings.com/user/CrizOstar)