Tax Guide Form 1120S: How to Report Taxes on an S Corporation This post was updated in April 2018 Form 1120S: U.S. Income Tax Return for an S Corporation Moving on through PDFfiller’s review of the tax forms, this post focuses on ... Tax Guide Doing Your Share with the 1120 S Schedule K 1 IRS 1120 S Schedule K 1 and your role as a shareholder Continuing with PDFfiller‘s review of corporate tax forms, we focus on IRS 1120 S Schedule K 1 ...