How do I file a form 15109 “request for tax deferment” for a military combat zone exclusion

If you received a CP04 letter, complete the form and send it to the IRS in the envelope enclosed with the notice, along with the required supporting documents by the due date on your notice. You can also fax this form to the IRS at 855-233-8562.

For additional information please see this article on the IRS website:  Understanding Your CP04 Notice