How do you format front end typesetting here in stack exchange?

Question

When copying Wolfram language commands from Notebook front end to stack exchange how do you format here? For example,

\!\(
\*UnderoverscriptBox[\(\[Sum]\), \(\[Eta] = 1\), \(\[Tau]\)]
\*FractionBox[
SuperscriptBox[\(\[Lambda]\), \(\[Eta]\)], \(\[Eta]\)]\)

Should look like

At the very least how to do \[...greeks...]?

Answer 1

I copy and paste your expression into a notebook and it is like this,

Since this sum will evaluate, I wrap it in HoldForm and then apply TeXForm,

I copy this expression and wrap it in $$, like this

$$\sum _{\eta =1}^{\tau } \frac{\lambda ^{\eta }}{\eta }$$

and on the main site, but not meta apparently, and it renders as

This lets me put a math expression in a stack exchange post. But if I wanted to post usable code that is also readable, I could replace TeXForm with InputForm:

which, when copied and pasted here gives

HoldForm[Sum[\[Lambda]^\[Eta]/\[Eta], {\[Eta], 1, \[Tau]}]]

This is already an improvement, but if you want to go a step further in readability, you can use the plugin described here (as pointed out by Rohit in comments), and get

HoldForm[Sum[λ^η/η, {η, 1, τ}]]