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