In the rich text editor:
@M3iz3
In a comment:
[M3iz3](https://chowlings.com/user/M3iz3)
For Names and Avatars:
In the rich text editor:
%M3iz3
In a comment:
[![M3iz3's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/M3iz3) [M3iz3](https://chowlings.com/user/M3iz3)