How can I transform a projection from WGS_1984_Web_Mercator_Auxiliary_Sphere to NAD_1983_StatePlane_Ohio_South_FIPS_3402_Feet? I've tried everything I can think of. As usual, when I look at on-line help, it tells me to use tools that do not exist on my ArcMap. Where the transformation tool SHOULD be, under Data Management -> Projections and Transformations, there's no there there.
Are you trying to re-project data from Web Mercator to the Ohio State Planes projection? If that's the case, the Project tool should do the trick.
The tool will output a new dataset that will be transformed from the Web Mercator into the Ohio State Planes projection. Here's a video, if you're unfamiliar with the workflow:
If I'm mistaken about what you're trying to do, apologies! But hopefully, this helps!