Well, someone can help me, in the year 2019-2020 I did not fill out my taxes, I would like to know if someone can help me how to fill that year? once I also had identity theft so every year I get a n

once I also had identity theft so every year I get a new pin, the question is should I use last year's pin?  because this year I get a new one but in my opinion it is for taxes 2020 -2021 Thank you