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