Petition for (Custody) (Visitation). These forms and instructions are available in the General Clerk's Office, Room 108, in the Nassau County.Child Support, Visitation, Custody and Paternity Petition Forms. Complete General Form 17 to petition for custody or visitation. If you prepare your own petition, file it with the Clerk of Family Court on the 11th floor of the courthouse at. Print your name, fill in the date, and sign the form. If you need additional assistance with this form, contact the family law facilitator in your county. Learn about child support, custody, and parenting time in non-dissolution cases. Find out who can file, how to establish paternity, and more.