In the rich text editor:
@kayo
In a comment:
[kayo](https://chowlings.com/user/kayo)
For Names and Avatars:
In the rich text editor:
%kayo
In a comment:
[![kayo's Avatar](https://chowlings.com/images/avatars/18.png?v=1658306105)](https://chowlings.com/user/kayo) [kayo](https://chowlings.com/user/kayo)