How do I obtain an overpayment made via EFTPS in 2019 toward my 2020 taxes?

When you file your taxes you enter the amount of estimated taxes that you paid for the year and, if that's more than you own you should receive a refund. 

I appreciate the attempt at an answer, however,  the money that was paid via EFTPS had to be handled separate from the customary way that a refund is traditionally handled.  Had I included the EFTPS  payment amount in the Turbo Tax field suggested, I suspect the return would have ultimately been rejected. Thanks.

If the tax paid through the EFTPS was assigned to your form 1040 for 2020, then you can enter the payment in the estimated tax section in TurboTax and you will get credit for it on your personal tax return this year.