You could use either one. Both are correct. Formal - I am well. Informal, but the most common. - I am good. You can also use "I am great/fantastic/doing okay/ feeling alright." I hope I helped! Sincerely, Tutor Stephanie M.

"I feel well today" means you feel healthy. You'd normally say this if you've recovered from an illness. "I feel good today" means you have a positive mood.

I'm a U.S. native. I agree with Peachey. "I feel good" refers to mood, "I feel well" to health. Thus, "I feel good" is a much more common, everyday thing to say. Also, you would usually say "i feel well" only in response to a question about your health.

I think both are correct, but i prefer I feel good today

Not sure but I would say " I am well today" and "I feel good today".