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