In the rich text editor:
@Carmen-v2
In a comment:
[Carmen-v2](https://chowlings.com/user/Carmen-v2)
For Names and Avatars:
In the rich text editor:
%Carmen-v2
In a comment:
[![Carmen-v2's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Carmen-v2) [Carmen-v2](https://chowlings.com/user/Carmen-v2)