BNB Vault is a platform provided by Binance that allows BNB (Binance Coin) holders to earn rewards from various sources within the Binance ecosystem. By staking BNB in the BNB Vault, users can earn daily income through activities such as BNB DeFi Staking, Flexible Savings, and Launchpool. It essentially involves lending your BNB coins to the exchange in order to receive a percentage back in the form of rewards. BNB Vault aims to provide users with the best APR (Annual Percentage Rate) returns. If you need more information or assistance on how to use BNB Vault, you can refer to the official Binance support documentation or watch tutorials on the Binance official YouTube channel.