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