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