BNB is a service token and payment vehicle in the Binance ecosystem, which includes the cryptocurrency exchange Binance, Binance DEX, and Binance launchpad, and many-many other crypto-projects.
BNB raised funds from crypto investors through an initial public offering (ICO) in 2017, before the launch of the Binance crypto exchange. BNB was originally issued on ERC-20 (Ethereum network standard), with a limited issue of 200 million tokens, and 100 million BNB were sold during the ICO.
After the launch of the Binance Chain core network, ERC-20 BNB standard tokens were converted at a rate of 1:1 to BEP2 BNB standard coins. Some of the tokens of the etherium network were burned using a smart contract.
Binance's blockchain is built on the Byzantine Fault Tolerance (BFT) consensus algorithm. Validators are responsible for making the blockchain network work and confirming blocks, and they are paid for this work.
You can buy and sell BNB on Binance crypto exchange using fiat currencies in a traditional way (bank wire transfer or card) or for cryptocurrencies using comfortable exchange functionality and lots of trading pairs.
One of the pluses of Binance is the ability to convert crypto into fiat and withdraw it to your bank card.