Setting up Mathjax ↗ for your website allows you to add mathematical symbols as either inline math $E = mc^2$, or display math: \[ R_{\mu \nu} - \frac 12 g_{\mu \nu} R + g_{\mu \nu} \Delta = \frac{8\pi G}{c^4}T_{\mu \nu} \] Such mathematics are written in LaTeX format ↗. If you already have old Mathjax 2 setup, you can use Conversion tool ↗ to migrate.

To setup the math from zero we enable inline math to be entered using dollar symbols $E = mc^2$ or display math by using escaped square brackets:

\[
    R_{\mu \nu} - \frac 12 g_{\mu \nu} R + g_{\mu \nu} \Delta = \frac{8\pi G}{c^4}T_{\mu \nu}
\]

The code to enable such math on your website is added to the head tag.

<head>
    ...

    <script>
        window.MathJax = {
            tex: {
                inlineMath: [ ['$','$'] ],
                displayMath: [ ["\\[","\\]"] ],
                processEscapes: true,
                autoload: {
                    color: [],
                    colorv2: ['color']
                },
                packages: {'[+]': ['noerrors']}
            },
            options: {
                ignoreHtmlClass: 'tex2jax_ignore',
                processHtmlClass: 'tex2jax_process',
                renderActions: {
                    addMenu: [0, '', '']
                }
            },
            loader: {
                load: ['[tex]/noerrors']
            }
        };
    </script>
    <script src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js" id="MathJax-script"></script>
</head>