Process for getting iPhone fixed?
 

My iPhone 4S started going crazy, out of the blue, on Sunday. Siri talks nonstop, cannot navigate through the dashboard, cannot get into settings, etc. I turned it off, on, same thing.

What is the process for getting it fixed? It is from Verizon. Do I go to Verizon or do I go to the Apple Store? If the Apple Store, do I schedule an appointment first?

Sounds like software to me. Have you tried a full restore from your back up?

To answer your question, if you have an apple store nearby, I'd take it in there, and yes, book an appointment first.

Open bin, throw iPhone in, close bin. Fixed!