This document is a guide that outlines the FedNow Service, which was launched in 2023 to facilitate immediate and irrevocable payments across U.S. financial institutions, available 24/7 throughout the year. Developed by the Federal Reserve Banks, the service aims to enhance the network for instant payments, particularly benefiting smaller regional banks and credit unions. The document compares the FedNow Service with the RTP network, which has been operational since 2017 and currently serves 65% of U.S. demand deposit accounts. It details the capabilities of both networks, emphasizing the advantages of using the FedNow Service alongside the RTP network for seamless transactions. The guide also discusses the types of payments available through the FedNow Service, including account-to-account transfers and various business payment methods. Additionally, it highlights the immediate availability of funds, rich data for transactions, and the finality of payments, ensuring a reliable and efficient payment process.