Form 941-X, Adjusted Employer’s Quarterly Federal Tax Return or Claim for Refund, is the form employers use to correct errors on a previously filed IRS Form 941. As a brief recap, employers use Form 941, Employer’s Quarterly Federal Tax Return, to report employee wages and payroll taxes each quarter. On Form 941, you must report things like wages paid to employees, FICA (Social Security and Medicare) tax, and federal income taxes.