Mailing addresses for Forms 941 ; Department of the Treasury Internal Revenue Service Kansas City, MO 64999-0005. Internal Revenue Service PO Box 806532To request your refund, you must complete Form 941X, Adjusted Employer's Quarterly Federal Tax Return or Claim for Refund. Complete the top employee authorization portion of the Employer Affidavit; and,; Submit the form via mail to: Arizona Department of Revenue. As a business owner (SCorp) I pay monthly tax deposits towards quarterly tax return, form 941. I accidentally overpaid deposit for May 2017. Withholding returns must be filed electronically for taxable years beginning from and after December 31, 2019. If there is an overpayment you can either apply to the next Form 941 or request a refund. A true overpay will require your wife to repay that amount, there is no law that shields your wife from this, however. This guide provides the basics of the 941 form, instructions to help you fill it out, and where you can get help meeting all your payroll tax obligations.