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