Taxes are pay-as-you-go. This means that you need to pay most of your tax during the year, as you receive income, rather than paying at the end of the year. The Underpayment of Estimated Tax by Individuals Penalty applies to individuals, estates and trust that don't pay enough estimated tax on their income or you pay it late.
https://www.irs.gov/payments/underpayment-of-estimated-tax-by-individuals-penalty
