So I talked to my friend with an emotional support dog and researched a ton about service dogs. I learned that emotional support dogs can only live with you or fly inside of an airplane with you. They don't have to be fully trained, but they do have to be good on a leash and listen to you. You need a letter from a doctor in order qualify. More on getting a letter from a doctor for your dog
here.
Service dogs have to be fully trained and can basically go anywhere with you. They are protected by the
ADA laws here. You don't need a letter from a doctor and you don't have to register them, but some people do recommend a service dog registration
here so you can identify it as a special animal. Also, I found out that you don't NEED a harness or vest when you go out with them.
I am looking to adopt a small to medium sized dog from my local shelter and getting them a letter for now while I look to train them. I can do it!