In the rich text editor:
@republic_art
In a comment:
[republic_art](https://chowlings.com/user/republic_art)
For Names and Avatars:
In the rich text editor:
%republic_art
In a comment:
[![republic_art's Avatar](https://chowlings.com/images/avatars/1594.png?v=1659384089)](https://chowlings.com/user/republic_art) [republic_art](https://chowlings.com/user/republic_art)