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