Q. Can I still file tax even if I did not work in 2020 and/or are otherwise not required to file?
A. Yes. But, you need to explain what you are trying to accomplish.
If it's for the stimulus payments, there was a non-filer tool available at irs.com to do that. That is no longer available and you will need to file a 2020 return to get the 2020 Recovery rebate credit (stimulus). People who qualified as dependents, in 2020, are not eligible for the Recovery rebate credit .
If it's about child credits, the money you hear about people getting for just filing a tax return claiming kids requires them to have some earned income (wages or self employment). Without earned income, they are not eligible for the "refundable" Earned Income Credit or Additional Child Tax Credit. Both credits are calculated on the amount of earned income you have. No earned income means no "refund". A small amount of earned income means a small refund. For 2020, the child tax credit does not "kick in" unless you have at least $2500 of earned income. For 2021, the rules are different, and you will not need earned income to claim the Additional Child Tax Credit. But, you will not file your 2021 tax return until early 2022.
A child can be the “qualifying child” dependent of any close relative in the household. If you live with someone else, e.g. your parents, it may be better if they claim your child.
Instead, you could allow the non-custodial parent to claim the children. Non-custodial parents are allowed to claim the child tax credit, but not the Earned income credit.
If you are a student, over age 23, and are not claimed as a dependent by someone else (e.g. your parent) you may be eligible for the up to $1000 refundable American Opportunity (tuition) Credit. That credit is not dependent on having either kids or earned income. You must be at least a half time undergraduate student. There's even a loop hole available to claim the credit, if you are on scholarship.
