What does writing not for deposit for EFT only on a check do?

Writing "not for deposit" and "EFT only" on a check indicates that the check cannot be deposited into a bank account but can be processed electronically through an Electronic Funds Transfer (EFT). This designation ensures that the funds are transferred directly to the intended recipient's account without allowing the check to be cashed or deposited elsewhere. It helps prevent unauthorized use of the check while facilitating a secure electronic transaction.