If you haven't already filed your return, revisit the estimated payment calculation interview. On the Review Your Estimates for 2018 screen, answer Yes when asked Do you want to adjust your income or deductions? Then when you continue through the interview you'll be able to make adjustments so the voucher amounts will be in the ballpark.
To revisit the estimated payment calculation interview, follow the instructions in this FAQ: How do I print estimated tax vouchers for my 2018 taxes?
If you've already filed your return, you may print blank vouchers and instructions (click here) or make estimated tax payments online (by clicking "Direct Pay" at the IRS Paying Your Taxes web page).
