Children have a legal right to be supported by their parents. Parents have a legal obligation to financially support their children.
When parents live together, they support their children together.
When parents live apart, there needs to be a system to assure that children are fairly and consistently supported.
Every state has a guideline system to identify the amount a noncustodial parent must pay a custodial parent as “child support,” an amount intended to help a primary parent meet a child’s ordinary day-to-day expenses.
Every state also has systems in place to help monitor and collect those payments.