To apply for Innocent Spouse relief, File Form 8857, Request for Innocent Spouse Relief. Attach a statement explaining why you qualify for relief. Please write your name and social security number on any attachments. Where to File Mail your completed Form 8857, Request for Innocent Spouse Relief, to one of the following addresses. If using the U.S. Postal Service: Internal Revenue Service P.O. Box 120053 Covington, KY 41012 If using a private delivery service: Internal Revenue Service 7940 Kentucky Drive, Stop 840F Florence, KY 41042 The length of time to process your request could increase if you mail your completed Form 8857 to any other office. Alternatively, you can fax the form and attachments to the IRS at 855-233-8558.