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