Weather you worked or not in 2021 is not a factor in determining your need to file. If you received any reportable income then you're required to file. Generally, if the income received exceeds your standard deduction you're required to file. If you received self-employment income in excess of $432 then you're required to file. If you received investment income in excess of $1050 then you're required to file. If you received any advance tax credits you're required to file.
