If you make an electronic payment, you don’t need a paper voucher, since your payment is automatically linked to your social security number.
www.irs.gov/payments
Select 2021 estimated taxes or 1040-ES as the reason for the payment.
When you prepare your 2021 return, you will enter the estimated payment on the Deductions and Credits page under “Estimates and other taxes paid”. If you over-paid your estimate, the excess will be added to your refund.
