These forms and instructions are available in the General Clerk's Office, Room 108, in the Nassau County. Petition for (Custody) (Visitation).Complete General Form 17 to petition for custody or visitation. To start your case, go to a Family Court clerk and ask them to help you file a Petition for. " You can get the forms in the courthouse or you can file a custody or visitation modification petition online through the NY Courts website. In this video we'll cover three terms to always include in the plan the steps to file for custody in New York and how to modify a custody agreement. 2. Visitation (Parenting Time). Dated (specify date):. In general, Texas has very few official legal forms. This is why you will not always find a free fill-in-the-blank form for your situation.