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