In the rich text editor:
@Eee1
In a comment:
[Eee1](https://chowlings.com/user/Eee1)
For Names and Avatars:
In the rich text editor:
%Eee1
In a comment:
[![Eee1's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Eee1) [Eee1](https://chowlings.com/user/Eee1)