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