Per IRS Instructions for Form 1120-W Estimated Tax for Corporations, on page 1:
For S corporations, per IRS Instructions for Form 1120-S U.S. Income Tax Return for an S Corporation, on page 4:
Generally, the corporation must make installment payments of estimated tax for the following taxes if the total of these taxes is $500 or more: (a) the tax on built-in gains, (b) the excess net passive income tax, and (c) the investment credit recapture tax, each discussed later.
The amount of estimated tax required to be paid annually is the smaller of: (a) the total of the above taxes shown on the return for the tax year (or if no return is filed, the total of these taxes for the year), or (b) the sum of (i) the investment credit recapture tax and the built-in gains tax shown on the return for the tax year (or if no return is filed, the total of these taxes for the tax year), and (ii) any excess net passive income tax shown on the corporation's return for the preceding tax year. If the preceding tax year was less than 12 months, the estimated tax must be determined under (a).
To calculate estimated tax payments in the TaxAct 1120-S program:
Once you have completed that section of the Q&A, you can e-file them with your return or you may set up payments through the IRS Welcome to EFTPS online webpage.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the webpage or document at the time it is accessed.