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