ACH, or Automated Clearing House, is a network that facilitates electronic payments and money transfers between banks in the United States. It allows individuals and businesses to send and receive funds quickly and securely, making it a popular choice for direct deposits, bill payments, and other financial transactions. The ACH system processes large volumes of transactions in batches, which helps reduce costs and increase efficiency. Transactions typically take one to two business days to complete, making it a reliable option for both personal and commercial banking needs.