State tax filing

@macuser_22  "Only *2020* returns can only be amended online." -- that's not true. See attached screenshot. I am more confused than before. Why are you saying that only 2020 can be amended online? See attached screenshot. 

I want to know: how to amend 2019 federal and 2019 state? I did 2019 federal online and 2019 state using macOS app. Please state it clearly.