Mailing addresses for Forms 941 ; Department of the Treasury Internal Revenue Service Kansas City, MO 64999-0005. Internal Revenue Service PO Box 806532If, on the other hand, you've overpaid, enter the corresponding amount at Line 15. Form 941 is used to report income taxes, payroll taxes, Social Security, and Medicare taxes withheld from employee wages. The agency should have one employee fill out the entire form and then another employee audit the form for completeness, legibility and accuracy. Each Form 941 you file reports the total amount of tax you withheld from employees' pay during the quarter as well as the employer's share of payroll taxes. Bystep explanation on how to fill out Form 941. Payrolling is not permitted; each employer must file the Florida Business Tax Application (Form DR-1) with the. Department and report its own employees. 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.