it depends if you create an artifical refund, that would be illegal and then you can get into trouble.   each year stands on its own so if uyou have 3 years of tax info you need to file 3 ammual returns.      any year prior to 2019 you must buy the sofware since online prep and efiling are closed.  only 2019 can be prepared online and efiled. 

since i don't know what 3 years your talking about if you were due a refund for any year prior to 2016, it's lost.  2016 must be file by 4/15/2020 if you are due a refund fior that year.   if you owe, the same rule doesn't apply, the IRS can come after you forever.