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