Filling out incorrect information in a commercial invoice can result in delays or legal ramifications. It also causes shipping delays. You can use the commercial invoice for customs clearances while shipping to EU countries or other parts.  Any incorrect info could result in incorrect payment of duties and taxes. With this, you may encounter further legal implications. Also, people use commercial invoices for custom declarations purposes. Any misinformation may lead to underpayment. It could also affect the correct amount of duties and taxes.