In the rich text editor:
@aquawolfie
In a comment:
[aquawolfie](https://chowlings.com/user/aquawolfie)
For Names and Avatars:
In the rich text editor:
%aquawolfie
In a comment:
[](https://chowlings.com/user/aquawolfie) [aquawolfie](https://chowlings.com/user/aquawolfie)