IRS form 2210 line 1 starts with IRS form 1040 line 22 which is tax balance due after some credits are deducted.
If you filed the prior year tax return through your TurboTax account, select Tax Home in the upper left hand corner of the screen. Click the down arrow to the right of Your tax returns & documents.
If you filed with TurboTax the previous year but did not use the TurboTax account that you are in, see how to access your other TurboTax accounts.