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