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