I was told to use polyeurotheyne on my Terra Cotta pots before leaving them outside

Sure if you want to.
Helps to safeguard against cracking during freezing weather.

I called Minwax and theie products are for wood only.
Behr doesn't make one I can use.
What product do I purchase to protect my Terra Cotta pots?

I turn mine upside down for winter storage. It doesn't have to be polyurethane, it can be any type of waterproof cover.