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