All child support forms are categorized and linked below as downloadable files. Select the category you need to see the corresponding forms.You can use your tax return to reduce unpaid child support. You will need to put your SSN, Cause Number, Case Number, and your First and Last Name in the email. Note: This form also applies to some tax benefits, including the child tax credit, additional child tax credit, and credit for other dependents. Org to obtain these services. Complete an application if you would like to receive child support services. Under IRS rules, the parent who has primary custody of a child has the first right to claim that child on their tax return. Not every case involving child support payments are eligible for the Federal Tax Return Offset Program (FTROP). A Motion to Modify Child Support (CAFC102) form is the pleading filed with the court to make changes in the best interest of your child.