For what purpose?

No, they said you can use the 2019 earned income for the 2021 EITC lookback (assuming the 2019 income was more than 2021)

You cannot use the 2020 earned income for the EITC lookback in 2021.   

I think that entry was on the EIC worksheet last year, Im guessing its in the same place again this year.

You can open client 1040 form. Click on L27 (Earned Income Cr).

Just below L5 is the worksheet where you can select Prior year Earned income.