I am trying to describe a differential equation I am putting into NDSolveValue. However, it is complicated and I would like to express it in textbook form before I show how I have put it into Mathematica form. I have tried copying from traditional form but this does not work. Any suggestions?
Trying the suggestion I wish to copy the Laplacian so the Mathematica form is
Laplacian[\[Phi][x, y, t], {x, y}] then using TexForm
TeXForm[Laplacian[\[Phi][x, y, t], {x, y}]] which gives
\phi ^{(0,2,0)}(x,y,t)+\phi ^{(2,0,0)}(x,y,t)
You then have to put a $ before and after as a delimiter.
$\phi ^{(0,2,0)}(x,y,t)+\phi ^{(2,0,0)}(x,y,t)$
This is not converting to textbook form here but it works fine on the main site. Thanks for the suggestions.

TeXForm[]and copy it into the site, which supports MathJax. See this.$for inline display and$$for centered display. Also, MathJax is apparently not enabled on meta, unlike in math.SE.