If you did not have a 2210, then perhaps you got a refund in 2019 and did not owe federal taxes. If that is the case then you can put in $0 for 2019 owed.
Use Form 2210 to see if you owe a penalty for underpaying your estimated tax. The IRS will generally figure your penalty for you and you should not file Form 2210. You can, however, use Form 2210 to figure your penalty if you wish and include the penalty on your return.
TurboTax prompted me to check the box "Let the IRS figure my penalty" when I e-filed on 02/23/2021. The penalty amounts were relatively small to begin with, however should I be sending the IRS another payment (above and beyond the federal and state amounts I already paid in full) ahead of time?
I just don't know what to expect on when the bill from them will arrive, since I was not allowed to e-file on TurboTax if I included the Form 2210 for federal. I want to make sure I am not late when making the penalty payment - since I imagine it is subject to the 04/15/2021 tax deadline still. @Cynthiad66
Yes, you will send the payment for penalty when you receive the bill from the IRS. The IRS will figure any penalty for underpayment of estimated tax and send you a bill. If you file your return by April 15, 2021, no interest will be charged on the penalty if you pay the penalty by the date shown on the bill.