Where do I take a power of attorney form to be legalized after it has been notarized?

There is no such process I am aware of. Generally the POA is self executing. Not sure what you are trying to accomplish. If it has to do with real estate, ask your Title Insurance Company for guidance.

Once a power of attorney is signed, it is legal. Where you should take it sort of depends on what the power of attorney is supposed to accomplish. For example, if you want someone to have access to your bank account, you could give your bank a copy of the power of attorney. If you want someone to be able to consent to you obtaining medical care, you could leave your power of attorney with your physician or the local hospital. But by all means, give a copy of the power of attorney to the person you are authorizing to act on your behalf.

Nowhere. Once notarized it is in effect pursuant to its terms.

It is impossible to determine what your question means. I have no idea what 'legalized' means in this context. I wish I could help you, but I don't understand.