if your business income is from self-employment it was supposed to be included on Schedule C with your 1040. you not only owe income taxes on this income but also self-employment taxes. as others have said seek out a pro. depending on the amount of additional taxes involved, you could be billed for substantial penalties and interest for paying late and not reporting the income with your return. also, for the 2021 tax year, you may need to pay estimated taxes. payments were due in May and June so you face underpayment of estimated tax penalties when you file that return. estimated tax payments would also be due 9/15/21 and 1/15/2022
