Lets take for example the Laplacian. So I want to apply it in spherical coordinates, so I go the the associated documentation page (https://reference.wolfram.com/language/ref/Laplacian.html?view=all)

Luckily, there is an example Laplacian[{1, 1, 1}, {r, \[Theta], \[Phi]}, "Spherical"] // Expand. Yet still, I do not know whether \[Theta] is the polar or azimuthal angle.

As far as I can tell nothing in the docs tells you the order of arguments. Is it {radius, azimuth, polar angle} or is it {radius, azimuth, polar angle}?

Anyway, I tried

??Laplacian
??"Spherical"

to no avail.

So my question is where do I find the order of arguments of default functions like this? (If not in the documentation).

I can't keep coming to stack exchange for every single function I use. And trying all the permutations of the arguments until it works is rather tiring.

Is there a more in depth doc than the one I linked to? Also, what is the correct order of arguments in this case.