Mailing addresses for Forms 941 ; Department of the Treasury Internal Revenue Service Kansas City, MO 64999-0005. Internal Revenue Service PO Box 806532Where can you get telephone help? List your total deposits for the quarter on line 13. 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. Bystep explanation on how to fill out Form 941. • Lines 7a through 7c of Form 941. This guide will teach tax filers the basics of the 941 tax form along with detailed instructions to help you fill it out for your small business. Form 941 is used to report income taxes, payroll taxes, Social Security, and Medicare taxes withheld from employee wages.