# How does one add missing latex commands or see all available commands in math exchange site?

I wanted to write the \underbar in the [mathexchange site][1], but it wasn't possible when using \underbar{}. Is it possible to define my own commands for the math exchange site or how do I get access to all the available symbols for the site?

I'm not interested in debating to add features, I just want

1. to use the command I want to use

and

1. know a reference of all the available commands for future reference.

• All extensions in MathJax's core repository (ie that list) can be \required. – Peter Krautzberger Sep 27 '18 at 7:10