@ LenaH
I think user roberts298 had an overpayment on his 2020 return that he wants to apply to 2021 and is preparing estimated taxes for 2021, since that's the worksheet he was on. He was trying to do it in Forms Mode, however, and ran into a worksheet entry problem. So I told him how things flow between 3 worksheets, but also encouraged him to do it in Interview step-by-step mode instead.
@ roberts298 You may need to clarify/confirm exactly what you are doing so we can be sure which of the 2 scenarios you are referring to. Are you trying to get credit for a 2019 overpayment that you applied to your 2020 return, or did you have an overpayment on your current 2020 return that you are applying to 2021 and are now preparing 2021 estimates? The worksheet you mentioned is for the latter; i.e, preparing 2021 estimates, so that's what I assumed in my answer.
