the 1040 V is to accompany a check, money order that you send the IRS for the balance due on the 2020 return. you can also ignore it and make the payment through the IRS website
https://www.irs.gov/payments
you can also pay the estimates through the same site. the alternative is to increase your withholding so the total withheld is equal to last year + the amounts on each of the 4 1040-ES
put another way if you don't make the estimate payments your 2021 withholding must be 90% of 2021 tax or 100% (110% if 2020 AGI over $150,000/$75,000 if MFS) to avoid penalties
