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