In the rich text editor:
@Giuvell
In a comment:
[Giuvell](https://chowlings.com/user/Giuvell)
For Names and Avatars:
In the rich text editor:
%Giuvell
In a comment:
[](https://chowlings.com/user/Giuvell) [Giuvell](https://chowlings.com/user/Giuvell)