I am rolling my 403b into my Roth during tax year 2021. I have the extra money to pay the taxes. What tax form do I fill out to pay them? Will this prompt the IRS to make me pay quarterly? Can I pay it as lump sum? Thank you for your assistance.
Yes you can send in a one time estimate.
Here are the blank Estimates and instructions…..
Or You can pay directly on the IRS website https://www.irs.gov/payments
Be sure to pick the right kind of payment and year.....2021 Estimate
The payment is just an estimate. You will still need to enter the gross amount into your tax return next year and it will increase your income so the tax may be more. Then you will get credit for the estimated payment.