Child Support Forms ; 4-3b. Addendum to Support Petition– Request for Child Support (IV-D) Services.These are the official forms for use in Family Court proceedings. Use our printable child support demand letter template to require someone to pay their owed child support. Download it for free here. A custodial parent can waive or forgive all arrears owed to him or her directly. The Law Department assists local and out-of-state custodial parents in establishing an order of support from non-custodial parents. There is a free online child support calculator that figures out how much support a parent needs to pay. Learn how Ontario enforces child and spousal support payments.