Mailing addresses for Forms 941 ; Department of the Treasury Internal Revenue Service Kansas City, MO 64999-0005. Internal Revenue Service PO Box 806532This 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. Overpayment as a nonemployee, file Form 941 for each delinquent quarter. Bystep explanation on how to fill out Form 941. Division 10 is proud to present the Tenth Edition of the annual publication,. Overpayment returns are returns for which withholdings, credits, and estimated payments exceed tax after credits.