The MathJax filter parses Moodle texts and will fully render TeX expressions that it finds appearing within specific tokens.
The Mathjax filter also improves the look of buttons and preview within the equation editor that is part of the Atto text editor.
Site administration settings
The MathJax filter is enabled by default in Administration > Site administration > Plugins > Filters > Manage filters. Normally, the MathJax filter should be at the top of the list of filters.
The MathJax filter works without any additional configuration (using the MathJax Content Delivery Network). However, MathJax may also be installed locally if desired, to save on bandwidth or because of local proxy restrictions. See Administration > Site administration > Plugins > Filters > MathJax for further details and configuration settings.
MathJax has a setting for "TeX filter compatibility" that changes the behaviour to match as closely as possible, the "Tex filter". This means it will support all the different delimiters of the Tex filter, and display all equations as "inline". It is only recommended to enable this setting if you have existing equations written manually using a variety of delimiters supported by the old filter. It may be hard to determine if this is the case except by searching the database for equations of the form:
[tex] equation [/tex], <tex> equation </tex> or \( equation \)
The MathJax project is large and detailed with many options, which a Moodle admin can make use of with the MathJax filter.