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