If the IRS just sent you an IP PIN then it is to be used on ALL returns filed in 2023 ( read the notice carefully ) so you will put it on the 2021 return you are mailing in now AND use it on the 2022 return you will efile this year. FYI ... since they have no 2021 return on file yet when you go to efile the 2022 return the AGI to use will be a simple ZERO.
