I finished entering 1095-a information. the summary shows we owe $20,120. what would cause this?

[KittyM]

Generally, this would mean that you received too large of an amount of Premium Tax Credit based on your income for 2018 and owe a refund of the excess amount to the Health Care Marketplace.  This payment is processed through the IRS.  

If you do not have the funds to pay, you may request an Installment Agreement when you file your return through TurboTax or online at the IRS' web page Paying Your Taxes.